【A.】
sb. have no doubt to do
sb. have no doubt that 从句
sb. have no doubt about sth.
sb. have no doubt as to sth.
例如：I have no doubt about his success.
=I have no doubt that he will succeed.
我对他的成功毫不怀疑.
【B.】
there is no doubt 后面不可以跟to do 或doing,其固定用法如下:
1.There is no doubt that ...,即后面接that子句,如:
There is no doubt that she will keep her word.
毫无疑问她会遵守诺言的.
2.There is no doubt about sth.
There is no doubt about his innocence.
他完全是无辜的.
3.There is no doubt with sth.
There is no doubt with his faithness.
他的忠诚无可置疑.
4.There is no doubt as to ...
There is no doubt as to what he said.
有关他所说的话是不容置疑的.
5.There is no doubt of sth.
There is no doubt of it.
毫无疑问.
6.There is no doubt in ...
There is no doubt in his honesty.
他的诚实是无庸置疑的.
7.单独作插入语,如:
"There is no doubt, he is out.
“毫无疑问,他被排除了.”
【C.】
it is no doubt that ……
【D.】
由doubt组成的一些短语
（1）in doubt怀疑；拿不定主意.例如：
We are in doubt(about) what to do next. 我们不知道下一步要做什么.
When in doubt about the meaning of a word, consult the dictionary. 当你对一个词的意义没有把握时,就查一下词典.
（2）no/without/beyond doubt无疑地；必定；当然.例如：
It is no doubt difficult. 这无疑是困难的.
No doubt he didn”t mean to hurt you. 他肯定不是有意伤害你的.
Without doubt this is the best. 无可置疑,这是最好的.
Beyond doubt he will give you some advice on your study. 毫无疑问,他会给你的学习作一些指导的.
（3）make no doubt of 对……毫不怀疑.例如：
We make no doubt of his sincerity. 我们对他的诚意毫不怀疑.
She made no doubt of what he had said. 她对他所说的话毫不怀疑.
（4）throw/cast doubt on使人对……产生怀疑.例如：
Galileo”s experiments threw doubt on Aristotle”s theory of falling objects. 伽利略的实验使人们对亚里士多德的落体理论产生了怀疑.
What he had done cast doubt on his honesty. 他的所作所为使人们对他的诚实产生了怀疑.