How to form it: There are two variations for forming this tense. The meaning is the same or very similar for both variations.
- (will have) + (past participle). Example: They will have finished work on the hotel by the time we get there.
- (am/is/are) + (going to have) + (past participle). Example: They’re going to have finished work on the hotel by the time we get there.
THE BIG PICTURE:
Use this tense to:
- Express that something will happen before another action in the future.
Example: By the time you arrive in Prague, I will have already been there for two weeks.
- Express that something will happen by a certain date or time frame in the future. Note that the action will be completed. Example: By the end of next semester, Jay will have earned enough credits to graduate.
- Express duration by a certain date in the future. Example: As of June tenth, Bill have will worked for IBM for three years.