1编号：4162题型：单选题测试正确率：59.66%
—Were you at school when he came to see you? —Yes, I ______ a math class.
2编号：4157题型：单选题测试正确率：56.82%
When I came back yesterday evening, my brother ______ his homework.
3编号：4153题型：单选题测试正确率：59.66%
I met a good friend of mine while I______ on the street.
4编号：4146题型：单选题测试正确率：64.77%
—I called you at 4:00 yesterday afternoon, but no one answered. —Sorry, I ______ with my friends at that time.
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