I have no doubt _____ he will turn up on time.

题目

I have no doubt _____ he will turn up on time.
A.whether
B.that
K.if
D.what

答案

B.
因为其实这里是一个肯定句.I have no doubt的意思就是I am sure.由于是肯定的语气,所以从句不存在不确定的语气,所以选whether,if这几个原本和doubt搭配的词已经不适用了.所以从句用that来引导.