III. Simple future or Simple present.
I. Give verbs in the simple future or simple present.
21. We 'll go out when the rain ( stop ) will stop.
22. I ( stay ) will stay here until he ( answer ) answer me
23. Wait until I ( catch ) will catch you.
24. She ( not come ) won't come until you ( be ) are ready.
25. Miss Helen ( help ) will help you as soon as she ( finish ) finishes that letter tomorrow.

Ex 4
1. I haven't seen her for 3 years
    It's 3 years since I last saw her
    the last time I saw her was 3 years ago
2. they started learning English for ten years now
3. she has given up smoking since last year
4. Tom and Mary began working in that factory since 1990
5. I last wrote to you a month ago
6. I started living in Hue since I was an eleven-year-old girl
7. he last saw her twelve years ago
8. how long ago did you learned French ?
9. how long have you listened to pop music  ?
10. it is the first time I have tasted such a good cake
11. I last saw him 2 weeks ago
12. I have learned English for 7 years
13. this is the first time I have seen such a wonderful computer ( câu này mk k bk viết về It's ntn nên dùng this is thay thế
14. It's years since I last saw Anne