There is no doubt John will come by bus.A. ifB. whyC. thatD. how

问题补充：

There is no doubt John will come by bus.

A. if

B. why

C. that

D. how

答案：

A. if

B. why

(答案→)C. that

D. how

解析：考查同位语从句。Doubt作名词时，用在否定句中，后面 John will come by bus是doubt的同位语从句，且从句句意完整，要用that引导。所以选C。