FORM
will have been + verb’s present participle (base + ing)
=> will have been doing
Positive and Negative:
I will have been doing
I won’t have been doing
You will have been doing
You won’t have been doing
He/She/It will have been doing
He/She/It won’t have been doing
We/They will have been doing
We/They won’t have been doing
Interrogative and Negative Interrogative:
Will I have been doing?
Won’t I have been doing?
Will you have been doing?
Won’t you have been doing?
Will he/she/it have been doing?
Won’t he/she/it have been doing?
Will we/they have been doing?
Won’t we/they have been doing?
USE
Future perfect continuous is used when talking about actions that will continue up until a specific time in the future.
Moreover, it is used to project forward in time and look back at how long an action has been happening. The action will have started in a time in the past, present, or future, and is expected to continue in the future.
Examples:
His mother-in-law and Kara will have been waiting for him here for three hours by six o’clock.
By 2019, his family will have been living in Dubai for two years.
When the students finish this course, they will have been learning English for fifteen years.
Next year, Anne will have been working at Google for five years.
When the train arrives at 8:00, will you have been waiting for too long?
Remember:
Non-action verbs such as to be, to seem, or to know cannot be used in the continuous/progressive tense. Instead, the future perfect tense (will have + past participle) is used.
Examples:
Incorrect: In December, I will have been knowing you for a year.
Correct: In December, I will have known you for a year.
Incorrect: She will have been reading thirty novels by the end of the year.
Correct: She will have read thirty novels by the end of the year.