1) By the time my mother (to come) home I (to do) my homework.
2) While I (to read) yesterday my sister (to cook).
3) She (to clean) the house by the time I (to cook) dinner.
4) She (to say) that she (to go) there next day.
5) When I (to write) a letter my friend (to watch) TV.

1 came,had done

2 was reading,was cooking (cooked)

3 had cleaned,cooked

4 said, would go

5 was writing,was watching (watched)