9. ______ is mentioned above，the number of the students in senior high schools is increasing.

8. Go and get your coat. It’s ______ you left it.

7. You will be late ____ you leave immediately.

6. It worried her a bit ____ her hair was turning grey.

5. _____ she is young，she knows quite a lot.

4. ______ the day went on，the weather got worse.

3. The teacher didn’t leave ______ twelve o’clock.

2. ___ will do the experiment hasn’t been decided.

1. ____ will do the experiment comes to the professor’s office.

10. The moment he opened the window，a bird flew in.