doubt

There was still one little nagging doubt at the back of his mind..他的心头仍有一丝挥之不去的疑虑。

no doubt,adv. 无疑地；很可能地

in doubt,可怀疑的；不能肯定的

there is no doubt,毫无疑问

without doubt,无疑地；确实地

doubt about,v. 怀疑

have doubts about,怀疑

without a doubt,无疑地

beyond doubt,无容置疑，确实地

benefit of the doubt,假定其无过失或无罪（因无充分证据证明某人有罪）；裁判员对可疑情况无把握时不对有关运动员作不利判定

cast doubt on,引起对…的怀疑；对…产生怀疑

reasonable doubt,合理的怀疑

beyond all doubt,adv. 毫无疑问地

shadow of a doubt,辣手摧花（电影名称，又名心声疑影）

hang in doubt,悬而未决；还不能确定