问题描述：
Great efforts to increase grain production ____ if food shortage are to be avoided.
A.could be made B.must be made C.might be made D.would be made
为什么选B?这句话怎么翻译?
A.could be made B.must be made C.might be made D.would be made
为什么选B?这句话怎么翻译?
问题解答：
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