It is already well understood causes the global warming.A. whatB. whenC. howD. that

发布时间：2020-08-16 11:58:33


It is already well understood     causes the global warming.
A. what
B. when
C. how
D. that

网友回答

(答案→)A. what
B. when
C. how
D. that
解析：考查名词性从句。此题为it 作形式主语，真正的主语是后面的从句，从句中缺少主语，所以用what。
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