用所给词的适当形式填空

1. —What ______ (happen) to Jim last night?

    —He fell down and hurt his leg.

2. By the time he got to school, classes______ already ______  ( start).

3. I               ______( work)  out five math problems by the time the teacher came in.

4. When I got up this morning, my brother               ______( got)  into the bathroom.

5. By the end of last term, we              ______(learn)many English words.