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The students_____busily when Miss Brown went to get the book she_____in the office.
A、are writing, has left
B、had written,had left
C、wrote,left
D、were writing,had left
【正确答案】：D
【题目解析】：考查时态。句意：当布朗小姐去取落在办公室的书的时候，学生们正忙于写作业。故第一空用过去进行时，第二空用过去完成时。选D。