$\text{1.}$ stay

$\text{→}$ all weekend chia HTD

$\text{2.}$ went

$\text{→}$ last night chia QKD

$\text{3.}$ had

$\text{→}$ last year chia QKD

$\text{4.}$ was

$\text{5.}$ visited

$\text{→}$ last summer chia QKD

$\text{6.}$ are

$\text{7.}$ bought

$\text{8.}$ see

$\text{9.}$ ate

$\text{10.}$ are talking

$\text{11.}$ returned

$\text{→}$ yesterday chia QKD

$\text{12.}$ thought

$\text{→}$ Vì có was

$\text{13.}$ went

$\text{→}$ yesterday chia QKD

$\text{14.}$ has driven

$\text{→}$ for 20 mins chia HTHT

$\text{15.}$ arrived - was

$\text{→}$ Hd đang xảy ra (QKTD) thì 1 hd khác chen vào (QKD)

$\text{→}$ giữa 2 hd có when/ while

$\text{16.}$ will ask - have

$\text{→}$ Câu đk loại 1: S + will/ can/ may + V<infi> + if + HTD

$\text{17.}$ say

$\text{18.}$ tells

$\text{19.}$ walk 

1. stayed

2. went ( DHNB : last night)

3. had ( DHNB : last year)

4. was

5. visited ( DHNB : last summer )

6. were

7. bought

8. saw

9. ate

10. talked

11. returned ( DHNB : yesterday )

12. thought

13. went ( DHNB : yesterday )

14. drove 

15. arrived/was

16. would ask/ had ( Câu điều kiện loại2 :If + S + V-ed/V2,S  + would/could/should... + V-inf) 

17. said

18. told

19. walked

- Vì đầu bài đã bảo chia động từ ở dạng quá khứ rồi nên câu nào có DHNB thì mình ghi thêm vào cho bạn thôi nha.

 Cấu trúc thì quá khứ đơn: 

Tobe:  I/she/he/it/Danh từ số ít/Tên riêng + was

          We/they/you /Danh từ số nhiều +were

Động từ thường :  S + Ved/pp

CHÚC BẠN HỌC TỐT VÀ XIN CTLHN Ạ