1. have been learning ( dấu hiệu nhận biết là: for+ năm)
2. didn't work-wasn't ( last year)
3. want to pass-must study ( next year)
4. sent ( last summer)
5. was-thought-have learnt
6. went-hadn't enjoyed ( Before)
7. was doing-met
8. noticed-was
9. am having ( now) -had
10. am revising ( at the moment)
11. have already begun ( already- thì hiện tai hoàn thành)
12. think-do ( every week)
13. is-isn't
14. pass-will start ( if- câu điều kiện loại 1)
15. will go
16. can see-have become ( already- thì hiện tai hoàn thành)
NHỮNG TỪ TRONG NGOẶC LÀ DÁU HIỆU NHẬN BIẾT CỦA TỪNG CÂU