Purpose: Describing what will be done BY/UP TO/BEFORE a certain future point in time
Future perfect is used to indicate that an action/experience will be finished/accomplished at some future time. It can be thought of as present perfect from a future perspective.
- Present perfect: I've read almost every Harry Potter book.
- Future perfect: If I get that new Harry Potter book, I will have read everything by JK Rowling.
"By" is a big clue that you need to use future perfect:
- I hope that by next spring, I will have passed IELTS.
1. I have travelled to China, the US, and France. Next year, when I go to England, I will have toured four countries.
- I am referring to the experience of visiting these countries.
2. Active voice: By this time next year, we’ll have destroyed our rivals.
Passive voice: By this time next year, our rivals will have been destroyed.
- This is a prediction that by this time next year AT THE LATEST, our rivals will lose.
- Pronunciation: will have been destroyed = will’uv bin destroyed
3. Active voice: We are working on a lot of problems right now, but I think by next week, we will have resolved most of them.
Passive voice: We are working on a lot of problems right now, but I think by next week, most of them will have been resolved.
- Often, the word "by" before a future time is a clue that you should be using future perfect.
4. High up in the north in the land called Svithjod, there stands a rock. It is 100 miles high and 100 miles wide. Once every thousand years, a little bird comes to this rock to sharpen its peak. When the rock has thus been worn away, then a single day of eternity will have gone by. (Henrick van Loon)