The future perfect

The future perfect is used to talk about an event that will overlap with, or finish before, another event int the future.It can be used in simple or continuous forms.

1. They will have built the skyscraper by January.
2. By July, I will have been working here a year.

how to form

Subject + Will have + past participle + object + time phrase

Time phrase + Subject + will have been + present participle + rest of sentence.