I have my doubts about it我对此有疑问。

今天的几个句子还是有关表达不确定的：1.I wonder if she will come. 我不知道她是否会来。2. I'm not at all convinced.我根本无法确信。3. I'm afraid it's questionable if he will succeed.我认为他能否成功还不能确定。4.There is some doubt in my mind about his success.我对他能否成功心存疑虑。