How can you be certain of this?

你怎么能这么确定？

So certain of your world. Of what's real.

那么肯定你的世界，肯定什么是真实。

You seem fairly certain of the date.

如果你们想的话 我可以更精确。

He may continue his progress through the night uninterruptedly, certain of reposing himself.

它还可以整夜不间断的飞行，并且确保自己能得到充分休息。

She's more certain of the answer than Catherine.

她听起来要比Catherine更加有把握。

" I'm almost certain of it, " said Hermione grimly.

“我几乎可以肯定，”赫敏神情严峻地说。

My mechanical and reptilian logic are certain of it.

我的机械和爬虫逻辑相当确定。

Yes, I am. And how can you be certain of this?

是的 你何以确定？

They were both English; my young friend was certain of this.

他们都是英国人。这一点我这位年轻的朋友十分肯定。

" Oh, I'm certain of it. Might I see your lute" ?

" 噢，这当然啦。我能瞧瞧你的琵琶么？"

I can't be certain of what time I left the office.

我不能肯定我是什么时候离开办公室的。

The telling clause here is Unless he is certain of doing well.

这里的关键部分是“除非作者确认自己写得很好”。

Still, no one is certain of the actual identity of the model.

不过，没有人能确定这位模特的真实身份。

I've put water into the desert because I am certain of success.

我把水引向沙漠中因为我确信一定能成功。

" Dead, he's dead, you are certain of that" ?

" 死了，他死了，你确定？"

The second definition is, the feeling sure or certain of a fact or issue.

第二个定义是，对某一事实或问题有把握或确定的感觉。

You were certain of that, right? And not only was it a party school.

你们很确定这一点 不是吗? 不仅是个派对大学。

I was certain of the fact that this burning desire in her was unquenchable.

我非常确定，这股燃烧的希望在她心中不可撼动。

But our desire for quick answers may overpower the desire to be certain of their validity.

不过我们渴求快速的解答可能远胜於确认它们可靠性的慾望。

And you mentioned it to nobody else except your nephew, you're certain of that?

除了贵侄子外您没有对外人提起过，您确定吗？