1£®Looking at the sky£¬he was lost(lose) in thought at that time.

2£®What the professor wanted to emphasize (emphasize) in his speech is the importance of attitude towards study.

3£®Don't leave the engine running (run) while you are waiting for someone.

4£®In class you should fix your attention on what your teacher says.

5£®What he said was not related to our discussion.

6£®The student that/who/whom the teacher praised at the meeting is our monitor.

7£®The boy with whom John spoke is my brother.

8£®By the time I graduate next year£¬I will have lived (live) here for five years.

9£®I'm not in the least satisfied with the result.

10£®Every morning I go out to breathe(breath) fresh air.