This is certainly the case, but it is a mistake or not I don’t know. A. ifB. even thoughC

发布时间：2020-08-17 13:15:44

This is certainly the case, but      it is a mistake or not I don’t know.
A. if
B. even though
C. whether
D. that

网友回答

A. if
B. even though
C. whether
D. that
解析：引导宾语从句时,whether 和if常可互换,但如从句提前,则只能用whether。  
以上问题属网友观点，不代表本站立场，仅供参考！