题目内容
The trouble with such resources as coal, oil and gas ________ that they are not renewable.
[ ]
A.has been
B.are
C.have been
D.is
答案:D
解析:
解析:
该句主语为The trouble,所以谓语应用单数形式,可排除B、C两项;从句意看,该句说明的是一般情况,所以不能用现在完成时,而用一般现在时。
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