Use the required past tense.
1. We (be sure) they (talk) about her, because the (break off) as soon as she (enter)
2. No wonder she (be) very tired. She (walk) three miles
3. Mother (say) that she (look) for him two hours
4. It (be) the song he never (hear) before
5. He (write) the article ever since she (come) from the University
6. She (be) sixteen and just (come) back from the college for the holiday
7. The British Museum (be build) many years ago
8. It (snow) heavily since the yesterday evening and mother (not to allow) us to play in the yard
9. When he ( wake up) it (be) late morning
10. Ann (say) she (get) three letters from Dmitry the day before