单项选择The thing---she was not sure was that she failed in this exam_英语解答

单项选择The thing---she was not sure was that she failed in this exam
A which B that C about which D in which

人气：159 ℃　时间：2019-08-23 10:52:45

解答

C
be sure about sth.对某事不确定
which引导的定语从句,需要介词about