The flu is believed ________ by viruses that like to reproduce in the cell inside the human nose and

题目简介

The flu is believed ________ by viruses that like to reproduce in the cell inside the human nose and

题目详情

The flu is believed ________ by viruses that like to reproduce in the cell inside the human nose and throat.
A.causingB.being caused
C.to be causedD.to have caused
题型:单选题难度:中档来源:不详

答案

C
 在“sb/sth is/was+过去分词+不定式”句型中,如果不定式所表示的动作在谓语动词后面发生,动词不定式要用一般式。

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