题目：
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.
答案：
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