题目内容
Air pollution is really a big problem here, but nobody knows ________ to do about it.
[ ]
A.if
B.how
C.what
D.whether
答案:C
解析:
解析:
|
what作不定式to do的宾语. |
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题目内容
Air pollution is really a big problem here, but nobody knows ________ to do about it.
[ ]
|
what作不定式to do的宾语. |