Imperatives tell people what to do.

The root form of the verb alone can sometimes create imperative sentences.

Examples:
“Stop!”
“Shoot!”
“Fire!”

To make the imperative, use the root form of the verb.

Examples:
“Stay right there!”
“Take out the trash.”
“Pass me the salt, please.”

Negative imperative simply adds “do not” before the verb.

Examples:
“Don’t go there.”
“Don’t jump!”
“Don’t stay up late.”

If the speaker is included in the imperative, you can use “let’s” or “let us” before the verb.

Examples:
“Let’s dance.”
“Let’s go now.”
“Let us do it.”

Determining Imperative Sentences

Most imperative sentences end with a period or an exclamation mark.

Usually, command/imperative verbs are at the start of the sentences.

Examples:
“Take care!”
“Be brave.”
“Listen to me.”

Imperative sentences generally do not have a grammatical subject because it always take the second person (you) for the subject.

Imperatives are used for many different reasons.

1. To give orders or commands.

Examples:
“Get out!”
“Stay where you are.”
“Do not make a sound.”

2. To give warnings or instructions.

Examples:
“Watch out!”
“Keep going straight.”
“Preheat the oven to 325 degrees.”

3. To give advice.

Examples:
“You don’t look well. Go see a doctor.”
“Make sure to settle your bills on time.”
“Don’t worry about her.“

4. Making a request or wish.

Examples:
“Please wait outside.”
“Please follow the rules.”
“Have fun at the party!“

Special Cases of Imperative

With “do”

We add “do” before the imperative to make the sentence more polite.

Examples:
“Do make yourself at home.”
“Do understand the situation.”
“Do let go.”

With never, ever, always

Just like “do”, the words never, ever and always come before imperatives.

Examples:

“Never do that again.”
“Don’t ever talk back to your parents.”
“Always remember that.”

Imperative with subject

Sometimes imperative clearly includes the subject.

Examples:
“Somebody answer the door!”
“You stay out of it!”
“Everybody run!”

When and How Long ask for different things.

When usually asks for a specific point in time.

How long asks for duration of time, with a beginning to an end point.

When and how long often use different tenses and different verbs.

We can use the present perfect tense when talking about the connection of the present to the past. This tense is used to talk about actions that started in the past and is still ongoing and is most likely to continue in the future. For “how long” we usually use the present perfect tense.

There are “action” verbs that refer to actions or events that occur at a particular time, normally only once. In this context, these “action” verbs cannot be used with “how long” or expressing duration and should only be used with “when”. In this case, we use “status” verbs to show condition existing over a period time.

Examples:

Some common action/status pairs are as follows:

Using an “action” verb to indicate something that takes place over a period of time is a usual error.

Examples:

How long have you found out about his infidelity? X

How long have you known about his infidelity?

How long has she fell asleep? X

How long has she been sleeping?

How long have you bought the truck? X

How long have you had that truck?

Notice that all the statements above are using the present perfect tense which implies an ongoing occurrence. In the last sentence, it is talking about “still owning the truck”. Therefore, you have to use a “status” verb. In this case, instead of “buy” we use “have”.

( “Buy ” is an action verb therefore it cannot indicate something that has been happening over a period of time.)

We can also use “how long” to talk about events/situations that transpired completely in the past.

Examples:

Aside from length of time, “how long” can also be used to answer measured length of something.

Examples:

How long do you want your hair to be?

How long was the skirt she was wearing at the party?

How long is the bridge?

Even if you have been writing your whole life, a grammar checker can still prove very handy. With the growing number of assistive writing tools, we need to consider which one best meets our needs, and more so which can be relied upon? Of course, if you want a quick answer, most people will cite Grammarly. In this article, we will consider a few online contenders.

Ed tech, or educational technology, isn’t really new. Teacher and students alike rely on a plethora of tools to reinforce learning. In recent months, this reality has come front and center, as educational systems the world over have had to offer education remotely. Now more than ever, educators and learners are reaping the benefits of using different applications and platforms. Thanks to technology, education whether face-to-face or asynchronous, is bridging the gap in spite of adverse conditions.

The same boon of decades of technological advancement make a difference in upgrading competencies, soft skills included, particularly when the preferred mode of learning is of the independent sort. What if writing isn’t one of our strong suits? How do we know if we have written well? This is where grammar checkers come in. Writing becomes a breeze as errors are detected, misspellings are corrected, and sentence construction is improved.

The low-down on a grammar checker

Confidence in the application of a language is akin to becoming proficient. Grammar remains an ambiguous, tedious quagmire of rules unless otherwise applied. Your prowess in the use of grammar may have well been tested by a university paper you had to submit, or that pesky email you had to compose. You may have also found it daunting to prepare your resume. Not everybody has the time nor the drive to scour various grammar websites to look up some obscure reference on the use of the present perfect tense or the virtues of the semicolon for a one-time specific context.

Before test-driving any grammar checker, try to take into account the following aspects so that your text is well composed:

Orthography (spelling). Misspellings in a document or email can have a jarring effect on reading. Although English is your everyday language, it is important to investigate the spelling when you are not sure of a term. It is one of those nitty-gritty habits leading to mastery that simply cannot be done without. Words in English are tricky as sometimes just one misplaced or erroneously included letter changes the meaning of not just the word but an entire sentence, sometimes to a comedic extent.

Punctuation. Whereas misspellings can be eyesores, erratic punctuation, or lack of punctuation altogether results in amateurish writing. We must be circumspect in the use of punctuation. Misplacing a comma alters the phrasing of words and may read differently as ideas get chunked the wrong way. We can thus say that punctuation plays to the ears, not just to the eyes.

Verb tenses. Since writing gives us the luxury of introspection and time to compose, it is imperative that we are surefooted in this temporal aspect of verbs, or risk losing our readers to time anomalies and anachronistic narrative.

Prepositions. These parts of speech are notorious speedbumps in navigating the writing process. While they are generally just two letters long, they are nonetheless important carriers of meaning. Repetition is key in remembering which preposition goes with which context, and as with other elements of a language, it takes trial and error in addition to research, to get a handle on correct usage.

Singular and plural words. A singular subject complements a singular verb. This may require laying out what we want to say mentally to avoid incorrect subject-verb agreement based on number.

Now that we’ve had a look at the specifics of language, which commonly leave us fumbling with word choice, lets talk about grammar checkers, particularly options that have been known to bolster good writing.

Ready?

Best free English grammar checkers

Don’t have a penny to your name to splurge on a grammar checker?

Not a problem. Free alternatives abound to help you assess the quality of text that you write. No checker is infallible so it’s your responsibility to give each one a try and get a better idea of each program’s capabilities. Here are our recommendations.

Scribens. With an eye to simplification, this free online grammar checker sniffs out annoying writing errors with just a few clicks of the mouse. Feature-rich, it offers not just grammar and spelling corrections, but also suggests improvements by way of pointing out redundancies, language register, awkward sentences, and verbiage.  The clever use of color makes it easy to spot corrections of a certain type, and a cursory glance at the statistics tab reveals information on reading time, speaking time, words per sentence, and readability just to name a few.

SpellCheckPlus. With a clean, minimalist interface, this corrector gets the job done by providing a summary of possible errors as well as a general rating of linguistic ability. The “Plus” in the site’s name doesn’t feel like it’s there just for effect; rather the site delivers in ways that other grammar checkers do not. Not only does it spot errors and gives corrections, but it goes the extra mile by explaining succinctly, and even providing examples. Thus, each visit to SpellCheckPlus is also a teaching moment that generates invaluable insight as to common writing missteps and how best to avoid them. Moreover, ticking the “Anglophone” box on the homepage enables the site to make recommendations specifically for native speakers.

Reverso. More than a grammar checker, the site has a handy set of tools every proofreader needs: definitions, synonyms, conjugations, and grammar are all at your fingertips. Reverso seems geared toward the independent learner who wants to hone their writing skills, and browse through multiple tabs that elaborate on relevant content.

LanguageTool. This grammar checker boasts ease of use, and gives you the option to choose the regional variant of English that suits your proofreading needs. American, Aussie, Canadian, Kiwi, or South African English – LanguageTool has got you covered. Like any good grammar checker, it recommends possible improvements that you can make. Add to the mix grammar examples, correction of typographical errors, lessons for each error, and correction of conjugations, and you’ve got yourself an excellent tool to make your text stand out.

Ginger. Another site with a clutter-free interface, Ginger makes the grade because of some useful options. Located to the right of the grammar checker there is a sidebar with links to topics in English that are sure to add polish to your writing. Here you can brush up on grammar rules including the parts of speech, often interchanged words, and some notorious “spelling demons.” The free version allows you to correct 300-character texts following the conventions of either American English or British English.

Virtual Writing Tutor. This site offers both a free version that allows you to check 500 words at a time and a membership tier that extends this capability to a whopping 3,000 words. Scrolling down the length of the homepage reveals the gamut of features at one’s disposal. In addition to correcting grammatical and spelling errors, it also keeps a keen eye on vocabulary and paraphrase. It helps you choose the best words according to the case, whether academic or colloquial, and it even tells you if you are using standard words. This checker also takes a fresh approach to honing writing skills by gamifying grammar practice. As if that weren’t enough, you can also put your grammar chops to the test with some online writing exercises.

RECOMENDED: Grammarly. It has a pretty good free version that corrects grammar, spelling and punctuation. You can also add it to your browser as an extension. We talk in more detail about its paid version below.

Hemingway Editor. With its considerable use of white space, this site is a breath of fresh air in a sea of busy bells and whistles. Form reflects function as readability is the name of the game with this editor, which bears the same appellation as a literary great. The online app points out which sentences in your text are too complex to read, as well as any superfluous use of adverbs and the passive voice, among other things. It rounds out our list of free sites, and is a great complement to any of the aforementioned grammar checkers.

It’s your turn! Try each of our recommendations, and choose the ones that meet your needs. Each has something unique to offer. After all, the proof of the pudding is in the eating, and the same applies to writing.

Best paid grammar checkers

If you’re not scraping by and if the bulk of your work or school tasks involve writing reports, emails, or essays, then investing in a paid grammar checker might be the way to go. As with the list of free sites, the following paid programs can give you a leg up on the competition.  

RECOMENDED: Grammarly. A fan favorite and byword for effective writing, this proofreader harnesses the power of AI to give you the best assistance possible. This includes the option of defining a goal for the proofreading task before placing your text in. That is, do you need to tell a story, describe, or report? Is the audience general, or are they experts on a topic? Do you have to write formally or informally? The program helps you meet all these requirements for 139 USD a year.

Once you have your goals defined, Grammarly will offer:

• grammar and spelling corrections
• tips to improve writing
• a plagiarism checker
• punctuation suggestions
• writing style suggestions
• expert help

Stilus. The site easily stands out with its four levels of revision and a more affordable price. 60 euros per year get you not just a grammar checker, but also suggestions on how to improve spelling and style. Additionally, you can correct 200,000 or even a million words a month depending on which plan you choose. Other advantages include interactive correction; checks for linguistic precision and typography; and alerts for run-on sentences, redundancies and excessive use of words. Not to be missed are plug-ins for WordPress and Microsoft Word.

WhiteSmoke. A grammar checker that offers services for different use cases, it has three different packages: Web, Premium, and Business. The Premium option should suffice the proofreading needs of the average student or entrepreneur. For $79.95 per year you can get a spelling and grammar checker, translator, and plugins. Other features such as the punctuation mark checker, writing style checker, linguistic suggestions, and plagiarism checker will give your writing that professional touch.

So really, when you think about it, there are no excuses not to check your text! We have already shown you the best free and paid options currently out there to give your writing that added boost. Using any one of these suggestions will enhance your ability to spot mistakes and root them out. Furthermore, you’ll learn by applying grammar, which beats learning the same rules by rote any day.

Do you really need a grammar checker?

In the spheres of commerce and education, grammar will always be essential in every way. For as long as we need to put pen to paper, to record thoughts, and thrive and transact globally. There will always arise a need for coherent writing that informs and persuades.

However, let us be clear on this. A grammar checker will not teach you to write. It is designed to support or verify what you have written. Please don’t use any of these sites as a crutch. You should resort to their use after you’ve written down your ideas. Writing precedes editing.

But.. Which is the best grammar checker?

For us, whether you use the free version, or if you want to invest some money and go further, Grammarly hands down trumps other writing assistants in terms of usability and dominant market share. The latter bodes well since they are less likely to abandon development once you have got used to it.

What do you think of this article? Do you have a favourite? We would love to know if you have already used any of the above-mentioned sites. Do you know of any other grammar checkers that we may have missed? Share your experience with us!

Informally, if and whether can be interchanged. However, in formal writing, it pays to know the distinct uses of each. As a general rule, use if in conditional sentences. Use Whether to present two possible alternatives.

Uses of If and When

• We can use If and Whether in indirect questions. Use if or whether for indirect yes-no questions and questions with or. If is more commonly used than whether.

Call the parents and find out if any of them can volunteer for the cleanup drive.

I talked to him and asked if he’d take a taxi or if he’d drive from the airport.

• With or, it is more common to use whether especially when two or more alternatives in the indirect question are available.

After the class, the students asked whether they should take an exam, make a book report, or both.

• In more formal context, we use whether.

The suspect will be asked whether he would confess to his crime.

• From a business meeting, notice whether being used.

Carrie read an article that she’d written and the executives decided whether it should be published.

• Use or not with if and whether when talking about an alternative. Put or not immediately after whether or at the end. With if, only use or not in end position.

They texted Michelle to confirm whether or not she really got sick.

I texted Chase to confirm whether he really got sick or not.

He texted Angel to find out if she really got sick or not.

• To introduce clauses that comes after verbs that express doubts, use if or whether.

She isn’t sure if she can sleep. She’s too excited.

I didn’t study properly so I doubt if I’m going to pass the test.

We’re not sure whether we’ll be able to call you from the village.

Uses of Whether

• To talk about future plans or decisions, use whether before a to-infinitive.

She was thinking whether to study English abroad.

Some household chores, such as cleaning, need to be done by every member. Others, such as whether to iron clothes, can only be done by just one person.

• Use whether after prepositions.

Correct: I don’t think she worries about whether you are happy or not.

Incorrect: I don’t think she worries about if you are happy or not.

Common Mistakes in Using If and Whether

• Using if before a to-infinitive

Correct: He doesn’t know whether to save his money or just save it.

Incorrect: He doesn’t know if to save his money or just save it.

• Using if directly before or not

Correct: Can you tell me whether or not you are available for an interview?

Incorrect: Can you tell me if or not you are available for an interview?

• Using if after prepositions

[talking about a trip to Australia for a year]

Correct: They are not sure about whether they get good jobs after graduation. They just want to finish their degrees as soon as possible.

Incorrect: They are not sure about if they get good jobs after graduation. They just want to finish their degrees as soon as possible.

Should, Would, and Could are auxiliary verbs and are the past form of Shall, Will, and Can. In some instances, they are also used in different ways.

Take a look at the uses of Should, Would, and Could.

Uses of Should

• You can use Should when talking about probability.

He should be on his way here.

I don’t have a lot to do at work. I should finish earlier.

Are you going with us to the music festival? It should be fun.

• Moreover, you use Should when asking questions.

Should I take a vacation?

Shouldn’t he be practicing his speech?

Should we call 911?

• You can use Should when showing obligations.

Children should obey their parents.

You should study harder.

He shouldn’t be driving when he’s had some drinks.

• Should is also used when giving recommendations or advice.

You should use this color. It’s more vibrant.

They should take 88th Ave. It’s the quickest way to get to town.

She should consider all her options first.

• Lastly, you can use Should when expressing opinions.

I think we should all read the news everyday.

Children shouldn’t spend so much time using gadgets.

They shouldn’t have come here anyway.

Uses of Would

• Like Should, you can use Would when asking questions.

Would you like red or white wine?

Would he like to see his kid?

Would this much food suffice?

• Would is sometimes used when asking the questions ‘who’, ‘what’, ‘where’, ‘when’, ‘why’ or ‘how’.

What would they do to solve this problem?

Who would want to go out in this freezing weather?

Where would they spend Christmas?

When would she come visit her friend in Paris?

Why would he do such thing?

How would you like to pay?

• You can use Would when making polite requests.

Would you like something to eat?

Would he do it for her?

Would they go to the pharmacy and buy me some medicines?

• You can use Would when talking about hypothetical situations.

If I had a lot of money, I would buy a mansion.

I would like to meet and have a conversation with the president.

She would live in abroad if it weren’t so complicated to uproot her whole family.

Uses of Could

• You can use Could when talking about possibilities in present, past, and future tense.

Present: Adam could be the one who left the door unlocked.

Past: Martin could have been the one who ate all the cookies.

Future: Lena could quit her job soon. 

• Could is used as conditional of Can. It can be used in present, past, and future tense.

Present: If she had more time now, she could stay longer.

Past: Even if he had had more money last year, he couldn’t have returned to his hometown in the countryside.

Future: If I had more vacation days next year, I could travel more.

• You can use Could when making suggestions in the past and future tense.

Past: I could have met you when I went there last week.

Future: They could go to Maldives for their honeymoon.

• You can use Could when talking about abilities in the past form.

I could memorize songs more easily when I was a kid.

He could swim faster when he was in his 20s.

Two years ago, I couldn’t exercise for more than a minute.

• Lastly, you can also use Could when making polite requests.

Could I have some tea, please?

Could you take these documents to her office?

Could I take this bottle of wine home?

Do you think you know how to use the word “enough” well enough?

The word “enough“ means ‘sufficient for the purpose’. It is used together with a noun, an adjective, a verb, or an adverb. It also sometimes be a pronoun.

Enough + Adjective or Adverb

• “Enough” goes before an adjective and an adverb.

It is not hot enough to cook the meat.
Your performance is good enough to get a pay rise.
I couldn’t read the questions quickly enough and I wasn’t able to answer all of them.

Verb + Enough

• “Enough” follows a verb.

She makes sure she sleeps enough.
They feel that they don’t visit enough.

I think you’ve practiced enough.

Enough + Noun

• “Enough” comes after a noun.

We don’t have enough flour to bake a cake.
She hasn’t got enough money.

Are there enough people on your team?

The Pronoun Enough

• “Enough” sometimes also acts as a pronoun. It can be used without a noun provided that you already know what the noun is based on the context.

I need more papers. These aren’t enough.
A: Can she still be with him? B: She can’t anymore. She’s had enough.

Using Enough With an Adjective and a Noun

There are to possible ways to use “enough” with an adjective and a noun. However, the two sentences do not have the same meaning.

He hasn’t got a big enough car. (=The car is too small.)
They haven’t got enough big cars. (=They have big cars but they need more.)

The Phrase Enough Of

Use “enough of” before a determiner or a pronoun such as: a, an, the, this, that, my, your, his, you, them, and others.

We don’t have enough of these white sheets.
They’ve eaten enough of their mother’s lasagna.
There’s enough of them there to finish the project.

A subordinate clause, also known as a dependent clause, is a clause that just makes a sentence more detailed by providing more information.

Like any other clause, it also has a subject and verb. But as it doesn’t express a complete thought, it cannot be a standalone sentence. Hence, it is always combined with an independent clause to form a complete sentence.

After Franco died, Juan Carlos became the King of Spain.

My sister, who lives in Boston, gave me her laptop. 

You can date whoever you want.

Parts of a Subordinate Clause

• It is either a subordinate conjunction or a relative pronoun that introduces a subordinate clause.

Subordinate Conjunction

• A subordinate conjunction signals cause-and-effect or a change in time and place between the two clauses of a sentence.

Below is a list of some of the most common subordinate conjunctions.

After, As, As long as, Although, Because, Before, Even if, Even though, If, Now, Now that, Once, Since, Than, Though, Unless, Until, When, Whenever, Whereas, Wherever, Whether, While, Whoever

As long as you follow the recipe, you won’t go wrong with this dish.

Although she likes smoking, she has to quit soon.

You cannot just leave whenever you please.

Relative Pronoun

A relative pronoun introduces a dependent clause that is related to the topic of the sentence.

Below is a list of some of the most common relative pronouns.

which, whichever, whatever, that, who, whoever, whose

Types of Subordinate Clause

• A subordinate clause can function as an adverb, adjective, or noun.

Adverbial Clause

• This clause answers the questions: where, when, how, and why. It starts with a subordinate conjunction.

We danced until the wee hours of the morning.

After the delegates arrived, the summit commenced.

Robin wasn’t promoted because he couldn’t meet the sales target.

Adjective Clause

• This clause typically answers the questions: what kind or which one. It can be one of these two patterns: pronoun/adverb + subject + verb or subject (pronoun/adverb) + verb.

pronoun/adverb + subject + verb

Whichever color of paper you have is fine.

subject (pronoun/adverb) + verb

This company that closed the deal is a multinational.

Noun Clause

• This clause follows this pattern: relative pronoun + subject + verb.

Whoever the new boss dislikes is in serious trouble.

She can choose the dress that she wants.

What the singer did shocked her fans.

Stative verbs express a state rather than action. They are not used in the present continuous form.

Stative: You don’t know the truth. 

Incorrect: You are not knowing the truth.

Stative: He really loves his mom.

Incorrect: He’s really loving his mom.

Stative: They seem satisfied with the proposal. 

Incorrect: They are seeming satisfied with the proposal.

Uses of Stative Verbs

Stative verbs often express thoughts and opinions, feelings and emotions, senses and perceptions, and possession and measurement.

Thoughts and Opinions

agree, believe, doubt, guess, imagine, know, mean, recognize, remember, suspect, think, understand

Feelings and Emotions

dislike, hate, like, love, prefer, want, wish

Senses and Perceptions

appear, be, feel, hear, look, see, seem, smell, taste

Possession and Measurement

belong, have, measure, own, possess, weigh

Stative vs Action Verb

• Some verbs can refer to both state and action, depending on the context.
• In the first example, it is a mental state wherein you express an opinion. Hence, it is in present simple. On the other hand, the second sentence shows that the speaker is presently doing the action of thinking. That is why it is in present continuous.

Stative: We think it’s absolutely perfect.

Action: We are still thinking about it.

• Other verbs that can either be stative or action are the following:

agree, appear, doubt, feel, guess, hear, imagine, look, measure, remember, smell, weigh, wish.

Stative vs Action Verb: Have

Stative (Possession): We have an attic. 
Action: We are having a meeting ASAP.

Stative vs Action Verb: See

Stative (Opinion): I don’t see any reason why we shouldn’t hire her.
Action: I am seeing Batman Forever this weekend. 

Stative vs Action Verb: Be

Stative (Quality): He is very funny.
Action: He is being very funny. 

Stative vs Action Verb: Taste

Stative (Perception): These tacos tastes amazing.
Action: The diners are tasting the tacos.

Level: Beginner-Intermediate

Certain prepositions can be used in conjunction with nouns to emphasize, connect, or clarify ideas expressed in sentences. In this combination, the preposition always comes directly after the noun. Here are some of the most common prepositions used with nouns:

to

• This preposition indicates the recipient of an action, a destination, relationship, and limit.

Emily has an addiction to shopping.
My daughter had an adorable reaction to the puppy.
Mark has an intense dedication to his work.
The damage to the property is much worse than I thought it would be.

for

• Use this preposition to indicate an objective, a reason, duration of time, as well as specify the use of something.

There is always a reason for a change.
I attended the class for one year.
I have high hopes for humanity.

of

• This preposition expresses causality or the relationship between subjects, indicate belonging and reference, as well as to specify the number or an amount.

I am the cause of all his problems.
I took a photo of the sea.
A good number of people understand Chinese.
My son has a fear of the dark.

in

• This preposition expresses a conditional state of being, indicate a location, opinion, belief, feeling, color, shape, and size. It also specifies day, month, season, and year.

Call me in case you need me.
I am in my friend’s place now.
I noticed a little change in the season.
There appears to have been a delay in the shipment.

on

• Use this preposition to indicate a state of being, an intention, a surface of something, days and dates, and parts of the body.

She went away yesterday on business.
I will attend his party on the 15th of August.
His focus on success hindered his social life.
I wear my wedding ring on my finger.

at

• The preposition at is only paired with a few nouns. We used “at” to indicate a place and one’s activity. “At” is also used to refer an email address and time. Often, we use the preposition in conjunction with which.

There are people at the park.
I have little chance at winning this game.
Meet me at 5 p.m. tomorrow.

from

• From is only occasionally used with nouns. The preposition usually refers to two things at opposition with each other, or specifies an origin or starting point when used in conjunction with to.

The woman sought protection from her husband.”
His transition from rags to riches was something out of a fairy tale.

with

• Nouns combined with the preposition with a point to relationships and connections between two or more things.

What is the matter with you?
The teacher noticed a small problem with the project I submitted.
Her close relationship with her sister is admirable.
If you’re having trouble with the activity, ask your teacher for help.

about

• When paired with a noun, about means concerning or in regards to.

His anxiety about public speaking is so bad.
Do you have any information about the new law?
She wants to hear the story about the princess.

between

• A noun that takes the preposition between forms a comparison between two things.

She talked about the comparison between pop music and rock.
There is a conflict between good and evil.
Is there a difference between green onions and chives?

Level: Beginner-Intermediate

A noun is a person, place or thing, and an adjective is a word that describes a noun. Sometimes we use a noun to describe another noun. We can use a noun as an adjective when it follows a noun that it modifies. In that case, the first noun “acts as” an adjective.

• We write the “noun as adjective” and the real noun in several ways.

two separate words (bathroom door)
two hyphenated words (head-master)
one word (bedroom)

• The “noun as adjective” always comes first.

a race car is a car that you use in racing
a horse race is a race for horses
a car race is a race for cars
a love story is a story about love
a ping-pong ball is a ball for playing ping-pong
tennis shoes are shoes for playing tennis
an art exhibition is an exhibition of arts
a book shop is a shop that sells books

• The “noun as adjective” is singular. Just like a real adjective, the “noun as adjective” is never changing. It is usually in the singular form.

car race – car races
(NOT cars race, cars races)
footballer – footballers
(NOT feetballer, feetballers)
shoe cabinet – shoe cabinets
(NOT shoes cabinet, shoes cabinets)

• Some nouns look plural but we normally treat them as singular. When we use these nouns “as adjectives” they stay the same.

News:
a news reporter, two news reporters
Billiards:
one billiards table, two billiards tables
Athletics:
an athletics coach, two athletics coach

• When we use certain nouns “as adjectives” (clothes, sports, customs, accounts, arms), we use them in the plural form.

sports team – sports teams
customs officer – customs officers
clothes shop – clothes shops

• Just like adjectives, we can also use more than one “noun as adjective” together.

machine production costs: we are talking about the costs of producing machines
Spain football team coach: we are talking about the coach who trains the team that plays football for Spain
animal research center: we are talking about a center that researches into animals