重点讲解：
1. reward with 奖赏；奖励；酬谢；
She was rewarded for her efforts with a cash bonus.
她因自己所作的努力而得到一笔奖金)d|bRpMg*WXUy。
2. make sure 一定要；设法保证；
Make sure you are strapped in very well, or else you will fall out.
一定要系好安全带，否则会摔出去xc!QJ(ViHpO&ZQBT;r。
3. at first 最初；起初；开始时；
Dart, who had at first been very tense, at last relaxed.
起初，达特非常紧张，最后终于放松了下来+CFj6V7!z!gjes2^_[G。
4. at randowm 随机地；偶然地；
We received several answers, and we picked one at random.
我们收到了一些答复，并从中随机挑选了一个x^YjLuVks38。