在doubt 之后接的名词性从句（有的用that引导，有的用wh-word 引导），一般都是doubt的“同位语从句”。例如：

There is no doubt that the earth is becoming warmer. 

There is some doubt who will take the place of the nanager.

I have little doubt that Tom will come on time.

I doubt whether she will like the present we bought for her.

There was some doubt whether they would agree with me or not.

You should by now be in no doubt what it is.