◎ 题干
The letters for the boss ________ on his desk but he didn't read them until three days later.
[    ]
A. were put  
B. was put
C. put  
D. has put
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◎ 解析
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◎ 知识点
    根据n多题专家分析,试题“The letters for the boss ________ on his desk but he didn't read them until three days later.[ ]A. were putB. was put C. put D. has put…”主要考查了你对  【一般过去时的被动语态】【主谓一致】  等知识点的理解和应用能力。关于这些知识点的“档案”,你可以点击相应的链接进行查看和学习。