David doesn’t give up he has failed in the experiment four times.A. ifB. whileC. thoughD.

发布时间：2020-08-21 18:07:37

David doesn’t give up      he has failed in the experiment four times.
A. if
B. while
C. though
D. since

网友回答

A. if
B. while
(答案→)C. though
D. since
解析：连词辨析。if 是否，如果；while当……时，然而；though虽然，尽管；since自从……以来，由于。句意：尽管他在实验中已经失败了四次，但是戴维德还不放弃。故选C。
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