1. Bonpland was doubtful whether, even then, it was safe.
    即使如此，庞普朗还是怀疑这水是否安全。

2. But if he'd been able to speak with an educated accent in those early short comedy movies, it's doubtful if he would have achieved world fame.
    但假如他在早期那些短小喜剧电影中能操一口受过教育的人的口音，那么他是否会闻名世界就值得怀疑了，

3. Though we may enjoy reading about the lives of others, it is extremely doubtful whether we would equally enjoy reading about ourselves.
    我们都喜欢看关于别人生活的报道，但是否同样喜欢看关于自己生活的报道，就很难说了。

4. He is a doubtful character.
    他是个可疑的人物。

5. One woman admits she was doubtful until she tried Imedeen herself.
    一位女士承认自己在试用"伊美婷"之前是有怀疑的。

6. I am doubtful about the propriety of granting such a request.
    我怀疑答应这项要求是否合适.