8. He has not gone to Ha Noi before.
9. She has driven for one month.
10. We have eaten since it started to rain.
11. I have not had my hair cut since I left her.
12. He has not written to me for 5 weeks. 
13. We have not met for a long time.
14. How long have you had it ?
15. I have not had such a delicious meal before.
16. The last time I have seen him was 8 days ago.
17. My father has not visited me for 3 three months.
18. Nam doesn't play chess better than Hoa.
19. My sister will be eighteen next week.
20. He was able to finish his course because his uncle helped him.
      Chúc bạn học tốt !!!