Dùng các thì để chia các động từ trong ngoặc

1. Water (to boil) at 100 degrees centigrade.
2. I cannot go out because it (to rain)
3. The factory (to begin) operation last year.
4. When I (to call) at his house, they told me that he (to leave) an hour before.
5. On checking up his answers he found that he (to give) five wrong examples.
6. When I (to leave) home, it (to rain) and as it (to rain) since the morning, the fields were quite muddy.
7. Clouds (to gather) all day and now the rain came down in sheets.
8. They walked together through the busy street. He (to talk) to her of his work at hospital and she (to tell) him what she (to do) at the factory that week.
9. You (to speak) to my sister yesterday? - No, I (no to see) her for a long time. I (can) not remember when I last (to see) her.
10. I (to learn) English for the last two years, and now I (to study) Russian, too.
11. You (to go) to the cinema last night? - No, I (not to be) for three weeks.
12. Lend me your pen, I (to lose) mine.
13. While I (to walk) through the park with my friend last night, a man (to snatch) his bag from his hand and (to run) away. I (can) not run after him because it (to be) too dark to leave him alone. The police (not to catch) him yet.
14. When I (to come) to see them last night, they (to play) chess, they (to say) they (to play) since 7 o'clock.
15. We (to wait) here for half an hour now, so I (to think) she will not come. - She always (to arrive) late or you (to think) something (to happen) to her? I (not to know), but I (to think) we (to wait) long enough.