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- I think there is a train about 12 but do not know for certain. 我想12点有一班火车，但我没有把握。
- I think there is a train about12 but do not know for certain. 我想12点有一班火车，但我没有把握。
- In such conditions, we could be face to face with a unicorn and not know for certain what it was. 虽然，麟之出，必有圣人在乎位，麟为圣人出也。圣人者，必之麟，麟之果不为不祥也。
- I do not know for certain. 我确实不知道。
- Do you know for certain what will happen to him ? 你肯定他会碰到什么事吗?
- He may succeed,but I don't know for certain. 他也许能成功，但我不敢肯定。
- We don't know for certain when it happened. 我们不能肯定是在什么时候发生的。
- We may succeed,but I can't know for certain. 我们可能成功，但我不敢说肯定成功。
- I don't know for certain when he will come. 我无法确定他什么时候回来。
- It's too soon to know for certain. 现在还太早， 不知道确切情况 。
- Only thing I know for certain is. 我唯一明确知道的一件事情是。
- I know for certain that it will rain tonight. 我确知今天晚上会下雨。
- He may succeed, but I don't know for certain. 他也许能成功，但我不敢肯定。
- Only the Fates know for certain. 只有命运才了解。
- Anon is not known for guile or intricate schemes. 阿农从不耍阴谋诡计。
- We never knew for certain how it happened. 究竟是怎么发生的，我们始终未搞清楚。
- Nobody knows for certain what kind of man he is -- he's rather a lone wolf. 谁也不知道他是什么样的一个人--他总爱独来独往。
- I didn't know for certain where I should go at that time. 那时，我的确不知道该到哪儿去。
- Has not known for certain the rational number 未确知有理数
- And you can see the difference today: he's not known for talking in platitudes. 在现在你就能看出差别：他并不是以那些垃圾话而出名的家伙.;(学文化好啊！
