PAST PERFECT / PAST SIMPLE
1. I (to go) to work after I (to recover).
A. went? had recovered B. went, have recover

2. The conference (to begin) by 9 a.m.
A. began B. had begun

3. How you (to like) the weather?
A. did … like B. have … liked

4. When we went to the concert he (to join) us.
A. joined B. had joined

5. Alice wanted to know why her brother (to miss)
the train.
A. missed B. had missed C. has missed