1, I have my doubt about what he said.
2, It's hard to say.
3, That isn't exactly right.
4, It's not certain.
5, I hope you're right.
6, I can't say for certain who'll come.
7, It might be true.
8, There is no guaranty.
9, Not exactly.
10, I think you might be mistaken.
11, It depends.
12, I can't say.
13, I find it difficult to draw a conclusion.
14, I can't make up my mind.
15, I have no idea about it.
16, I'm not sure.
17, I think so.
18, I'm not too sure of it.
19, I hope so.
20, I can't tell who's more capable.
21, Let's leave it to chance.
22. Maybe.
23, Maybe yes, maybe no.
