B1:

1,was having

2,hasn't slept

3,has already brushes

4,informed

5,Did..drink

6,Why didn't you leave

7,were

8,Did you visit

9,hadn't acted

10,has just wrote

B2:

2,They didn't meet each other before came there

3,...mình ko thấy câu 3 đâu cả :v

4, We watched TV after I had finished all chores

5,Which channel will you watch before tune in this one

6,By the time we graduated,he has worked for 5 companies

7,Before he read the book,he hadn't bought it

8,I have just called her after they cancel the interview

9,They left when I called

10,Lesson had started by the time I came

=>
1/
1. had had
2. had not slept
3. had already brushed
4. had informed
5. Had you drunk
6. hadn't you left
7. had been
8. Had you visited
9. had not acted
10. had just written

2/

2. They had met each other before they came there.

4. We watched TV after we had finished all chores.
5. Which channel had you watched before you tuned in this one?
6. By the time we graduated, he had worked for 4 companies.
7. Because he had read this book, he didn't buy it.
8. I had just called her before they cancelled the interview.
9. They had left when I called.
10. The lesson had started by the time I came.