◎ 题干
The project requires more labor than _____ because it is extremely difficult.
[     ]
a. has been put in
b. have been put in
c. being put in
d. to be put in
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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 project requires more labor than _____ because it is extremely difficult.[ ]a. has been put in b. have been put in c. being put in d. to be put in …”主要考查了你对  【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。