Expressing Certainty and Uncertainty in English 用英语表达肯定与不确定 If you are sure or not sure about something, you can use below phrases and expressions to express your Certainty/Uncertainty. 如果你对某件事确定或不确定，可以使用以下短语和表达来表达你的肯定/不确定。 Asking for Certainty: 询问确定性： Are you sure? 你确定吗？ Are you sure about it? 你确定吗？ Are you certain about it? 你肯定吗？ Do you think it is true? 你认为这是真的吗？ Do you think so? 你这么认为吗？ How sure are you? 你有多确定？ Expressing Certainty: 表达肯定： Yes, I am certain. 是的，我肯定。 I'm a hundred percent certain … 我百分之百确定…… I'm absolutely sure. 我完全确定。 I have no doubt about it. 我对此毫无疑问。 I'm sure about it. 我对此很确定。 I don't think there can be any doubt about …. 我认为……没有任何疑问。 Of course. 当然。 I'm positive. 我确信。 I'm quite sure about it. 我对此相当确定。 I'm no doubt about it. 我对此毫无疑问。 I'm absolutely certain that… 我绝对肯定…… Expressing Uncertainty: 表达不确定： I'm not sure about it. 我不确定。 I doubt it. 我怀疑。 I'm not really sure about… 我不是很确定…… I don't know for sure… 我不太确定…… It's very unlikely. 这不太可能。 I have my own doubts. 我有自己的怀疑。 I don't think so. 我不这么认为。 I don't believe this is true. 我不相信这是真的。 There's some doubt in my mind that … 我心里有些怀疑…… I'm not a hundred percent sure. 我不是百分之百确定。 I don't know yet. 我还不知道。