`1`. Have been.

Có severl times `->` Chia thì HTHT.

`2`. Have studied.

Có so far `->` Dấu hiệu thì HTHT.

`3`. Have seen.

Có recently `->` Dấu hiệu thì HTHT.

`4`. Have you seen.

`5`. Have done.

Có already `->` Dấu hiệu thì HTHT.

`6`. Have never gone

Có never `->` Dấu hiệu thì HTHT.

`7`. Haven't seen.

`8`. Have ever meet.

`9`. Were.

Có in the past 3 day `->` Chia thì QKĐ.

`10`. Have visited.

`11`. Found

Có in the past 50 years.

`12`. Has improved/ left.

Cấu trúc : HTHT + since + QKĐ.

`13`. Bought/ Have worn.

Vế 1 có last (Dấu hiệu thì QKĐ), vế 2 có yet. (Dấu hiệu thì HTHT)

`14`. Haven't seen/ left.

Cấu trúc như câu `12`

`15`. Have just moved.

`#Study well`

1) are be

2) study

3)visits

4)saw

5) has done

6) go

7) haven't seen

8) met

9) were

10)visited

11)found

12)hasn't improved/left

13)bought/haven't worm

14)haven't seen/left

15)moving/are