题目内容
Every possible means ______ to prevent the air pollution, but the sky is still not clear.
A. is used B. are used C. has been used D. have been used
C
解析:
mean单数复数一个形式。在本题中代表单数。
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题目内容
Every possible means ______ to prevent the air pollution, but the sky is still not clear.
A. is used B. are used C. has been used D. have been used
C
mean单数复数一个形式。在本题中代表单数。