Every possible means to prevent the air pollution, but the sky is still not clear.A. is u

发布时间：2020-08-17 12:06:09

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

网友回答

A. is used
B. are used
(答案→)C. has been used
D. have been used
解析：C mean单数复数一个形式。在本题中代表单数。
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