1.gave (câu này đang là QKĐ nên động từ cũng phải đưa về dạng V2/ed)

2.was 

3.doesn't have (đang là HTĐ nên động từ vế sau cũng chia HTĐ)

4.had graduated (câu trực tiếp gains tiếp)

5.has worked /was

6.call

7.arrived

8.earn

9.have been

10didn't see

1. He bought a Vietnamese-English dictionary and gave it to me.

(Trước and dùng quá khứ đơn nên sau and cũng dùng quá khứ đơn)

2. The coffee was all right, ut the cream was sour.

(Phía trước dùng quá khứ đơn nên phía sau cũng vậy)

3. He has a piano and a violin, but he doesn't have a flute.

(Phía trước dùng hiện tại đơn nên phía sau cũng vậy)

4. He said that he had graduated from university in 1991.

(Hành động graduate from the university đã kết thúc trong quá khứ, nhưng do câu này là reported speech nên chia ở past perfect)

5. He has worked very hard since he was here.

(Trong câu có since nên động từ chính chia present perfect, sau since chia past simple)

6.  We have just come in when you called. 

7. I haven’t seen him since he arrived. 

(Sau since chia past simple)

8. He works on Sundays so that he can earn money to pay his tuition.

(S + can + V0)

9. I have been busy since we last met.

((Trong câu có since nên động từ chính chia present perfect)

10. I’m very fond of Jane but I have never seen much of her lately.