The students busily when Miss Brown went to get the book she in the office.A. were writing

The students busily when Miss Brown went to get the book she in the office.
A. were writing; left
B. wrote; had left
C. had written; left
D. were writing; had left

A. were writing; leftB. wrote; had leftC. had written; left(答案→)D. were writing; had left解析：状语从句（即when…）是过去时，主句动作和从句动作同时发生也应用过去时态，根据表达意义当老师进去时学生正在写，所以主句动作应该用过去正在进行时。she in the office这是定语从句，那本书是老师在取书之前放在办公室的，所以是动作发生在过去的过去，故第二空应该用过去完成时。

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