How many friends will you have spoken to by this time next week?
Which TV shows will you have watched by this time tomorrow?
Where will you have lived by the time you retire?
All these questions ask what 'will have' happened by some future time. Use the future perfect tense to talks about the past in the future.
Subject + will have + past participle + object
I will have finished by 5pm.
He will not have left for work. (negative)
Will the students have gone back to school in September? (question)
We often use the future perfect to talk about something that 'will have' happened up to a specific point in the future:
Now complete these future perfect sentences: