I know for a fact that baby corn is very expensive in Europe.

我确实知道玉米笋在欧洲是非常昂贵的。

Having said that, I did not know for a long time what I was looking for.

话虽如此，很长一段时间里，我都不知道自己追求的是什么。

We don't know for sure how much mass our Sun's lost over the last four billion years.

我们不知道我们的太阳在过去的40亿年里损失了多少质量。

I love books because they help me keep up with things I need to know for my profession.

我爱书，因为它们帮助我跟上我的职业需要知道的事情。

I don't know for certain why Carl Dadisman, the owner, wouldn't stop Daddy from sitting down.

我不知道出于什么原因，卡尔·达迪斯曼——这家店的店主——并不阻止爸爸坐下。

If your child regresses to babyish behaviour, all you know for certain is that the child is under stress.

如果你的孩子退步到幼稚的行为，你可以肯定的是孩子正处在压力之下。

Scientists are continually learning more about sleep, but one thing they know for sure is this—for humans, it is as important as food and water.

科学家正在不断加深对睡眠的研究，他们对其中的一件事实确信无疑：对于人类来说，睡眠与食物和水一样重要。

We'd probably know for sure whether someone was shooting at the president from that famous grassy knoll.

我们可能确定是否有人正在从那个著名的草地山丘草地上向总统射击。

Do you remember all years when scientists argued that smoking would kill us but the doubters insisted that we didn't know for sure?

还记得那些年吗？当初，科学家提出吸烟会导致死亡，而怀疑者们却坚持认为我们还不能确认这一点。

Just as on smoking, voices now come from many quarters insisting that the science about global warming is incomplete, that it's OK to keep pouring fumes into the air until we know for sure.

就像吸烟一样，现在来自许多方面的声音坚持认为，有关全球变暖的科学是不完整的，在我们确定之前，继续向空气中排放烟雾是可以的。

You can't know for sure.

你不可能确切知道。

However, we don't know for sure.

然而，我们仍然不能确信。

But Idon \ 't know for sure.

但我也不敢肯定。

We may never know for sure.

我们可能永远无法确定。

What do you know for sure?

您肯定的事情是什么？

How can you know for sure?

你怎么能把握得住呢？

Thomas just wanted to know for himself.

托马斯只是想知道自己是谁。

So, honestly, I don't know for certain yet.

所以，实话说，我都不知道究竟会是谁。

I don't know for sure.

我不能肯定。

That is the only thing we know for sure.

这是我们唯一确定的事情。

It's a good trick to know for readability.

它是一个提高可读性的小技巧。

But he added, he did not know for certain.

但是他补充说，他也不确定。

I won't know for another week if I'm available.

不知道下个星期有没有空。

Don't know for sure, but yes, I think there is some.

还不能确定，但答案是肯定的，我认为有些产品会是这样的。

One thing we know for sure — it is not the Higgs boson.

只有一件事我们相当确定——一定没有希格斯玻色子。