英汉词典

1. 未必的;不大可能的
    If it is doubtful that something will happen, it seems unlikely to happen or you are uncertain whether it will happen.

    e.g. For a time it seemed doubtful that he would move at all...
           有一段时间他似乎根本不会搬家。
    e.g. It is doubtful whether Tweed, even with his fluent French, passed for one of the locals...
           尽管特威德能说一口流利的法语，他是否能被当作当地人还很难说。

2. 怀疑的;疑惑的;拿不定主意的
    If you are doubtful about something, you feel unsure or uncertain about it.

    e.g. I was still very doubtful about the chances for success...
           我对能否成功仍然深表怀疑。
    e.g. Why did he sound so doubtful?
           为什么他听上去如此不确定？