15. Lots of trains used to stop here, but not many do now.

used to V-inf=thói quen trong quá khứ(đã chấm dứt ở hiện tại)

16. They were panting roses in the garden when I came to see them.

1 hành động xen vào hđ khác trong quá khứ-->hđ xen vào chia qkđ,hđ kia chia qktd

17. Jenny has seen the film many times because it’s very interesting.

hđ lặp lại nhiều lần-->chia thì htht

18. My sister practices playing the guitar twice a week.

practice + V-ing=luyện tập

19. He is trying to finish his project by the end of the month.

try + to V-inf=thử làm việc gì 

20. He is always making noise in class.

always-->dùng trong thì httd để than phiền về 1 thói quen xấu

21. Mr. John has just built a new house near my grandfather’s.

just-dấu hiệu thì htht

22. Could you tell me how to get to the nearest post office?

23. She suggests learning ten new words a day.

suggest + V-ing=đồng ý với đề nghị nào đó

24. I'm planning to write a letter to the company.

25. The local people are always throwing garbage into the rivers.

always-->dùng trong thì httd để than phiền về 1 thói quen xấu

26. I haven't fed my little dog yet.

yet-dùng trong câu phủ định,nghi vấn của thì htht

27. When I’m tired, I enjoy watching TV. It’s relaxing.

enjoy + V-ing=yêu thích làm gì

28. I don’t know what to do when I’m waiting for the bus.