1. didn't try-> haven't tried
2. has been-> was (know-> known, chủ tus có viết thiếu đề ko?)
3. enjoyed-> have enjoyed
4, played-> has played
5. knew-> have known
6. performed-> have performed
7. has met-> met
8. didn't see-> haven't seen
9. didn't see-> haven't seen
II:
1. What do they do at night?
When do they do their homework?
2. Who came to the party alone?
Bn học tốt!!