=>
5. Don't forget to write a letter to me. ( Don't forget to V : đừng quên làm gì)
7. When did you go to Sapa?
10. We are not going to buy a house in Ha Noi. ( be going to V = intend to V)
12. We haven't seen her since Christmas day. ( thì HTHT have V3/ed. since + mốc thời gian)
13. The last time we visited my grandfather was two months ago. ( the last time QKĐ)
14. I haven't written to my uncle since July.
17. They have learnt English since 1999.
18. How long have you learned English?
19. When did you buy this car?
20. Unless they go now, they will miss the train. (unless = if not)
21. Unless it rains, we will go camping.
22. Should you not believe what I said, ask your mother. ( đảo ngữ đk loại 1 should S (not) V)
23. Were I you, I wouldn't do that. ( đảo ngữ đk loại 2 )
24. Were he to work more slowly, he wouldn't make many mistakes. ( đảo ngữ đk loại 2 với động từ thường Were S to V)
25. If we had enough money, we would buy a new house. ( đk loại 2 -> không có thật ở hiện tại)
Các câu còn lại bạn làm đúng rồi.
