The students ______ busily when Miss Brown went to get a book she ______ in the office.A.w

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The students ______ busily when Miss Brown went to get a book she ______ in the office.

A.were writing; has left

B.had written; left

C.were writing; had left

D.had written; had left

请帮忙给出正确答案和分析,谢谢!

热搜:关于氨基酸代谢错误的论述是_________。

答案解析

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  • 正确答案:C
    考查时态。“把书忘在办公室”发生在“去取书”这一过去的动作之前,因此要用过去完成时。句中when表示某一时间点,某人在某一时间点做某事,用过去进行时。因此主句应该用过去进行时。故答案为C。