There is no doubt English is the widely used language all over the world.A. thatB. whether

问题补充：

There is no doubt English is the widely used language all over the world.

A. that

B. whether

C. if

D. how

答案：

(答案→)A. that

B. whether

C. if

D. how

解析：句意：毫无疑问英语在全世界广泛使用。这里使用that连接同位语从句，说明doubt的内容，如果是There is doubt后面就是用whether连接同位语从句，所以选A。