1.It is usually not possible to be certain of the history of a second-hand child seat.
它通常是不可能的某些历史的一个二手儿童座椅。
2.And remember, you don't need a certain number of friends, just a number of friends you can be certain of.
请记住，你不需要一定数量的朋友，只要有一些你可以确定的朋友就够了。
3.I don't need a certain number of friends, just a number of friends I can be certain of.
我不需要朋友达到一定数量，我只需要很多我信得过的朋友。
4.Similarly the principles on which your life is based may be entirely sound, but until you've examined them, you can't be certain of this.
与此相似，作为你的生活基础的那些原则，或许完全是说得过去的；但是，在你细究之前，你对此是拿不准的。
5.Whatever uncertainties the last few weeks may have brought I want you to be certain of this our work together will continue unchanged.
无论过去的几周我们多么不开心，有一点我希望是肯定的，那就是我们一定要坚持不变地在一起继续工作。
6.BACK in the 1980s, marketers could be certain of reaching 90% of American households with an advertisement on prime-time network television.
回顾上世纪八十年代，市场营销人员只需要在电视网黄金时间投放广告便可以确保对美国家庭的送达率达到90%。
7.To do this, the designer must be certain of the actual path that the return current takes in getting back to the signal source.
要做到这一点，设计者必须掌握电流的实际流向和返回信号源的路径。
8.As yet, she cannot even be certain of the degree of her own regard nor of its reasonableness.
迄今为止，她甚至都无法确定自己对他关注的程度是否妥当。
9.By staying indoors, they might miss out on some great skiing, but they can be certain of avoiding burial in an avalanche.
如只呆在室内，也许他们错过了一些美炒的滑雪过程，但他们能肯定能避免埋葬在雪崩中。
10.There is only one corner of the universe you can be certain of improving and that's you own self !
宇宙中只有一芥之地是你肯定可以改善的，那就是你自己！