certain/curtain/certainly/certainty/uncertain/sure/ensure/insure/insurance/assure
记忆：
1. certain 词根tain含义为hold, adj. 确定的, 某一个 It’s certain that a certain boy will be waiting for you at the gate of your home at that time. 那个时候肯定有个男孩在你家门口等你。 be certain of sth 对某事有把握 be certain that be certain to do sth It is certain that
2. certainly adv. 一定，当然 We will certainly win the game. 我们一定会赢这场比赛。
3. certainty n. 确定性 The certainty of the examination made the students worried.肯定要考试，学生们为此而担心起来。
4. uncertain adj. 不确定的 Whether the Arabians welcome the so-called democracy is still uncertain. 阿拉伯人是否欢迎所谓的民主还是一个问号。
5. curtain u, 联想帘状， curtain, 帘 How do you find my new curtain?你觉得我的新窗帘怎么样？
6. sure adj. 对....有把握, 可靠的 adv. 的确, 当然 I’m sure of our victory over them. They are sure to be defeated by us. 我肯定我们能打赢他们，他们肯定会被我们击败的。 be sure that be sure of sth对……有把握 be sure to do sth一定会
7. 加动词前缀en, 使……， ensure To make sure or certain n. 确保, 确保, 保证 Our precautions ensured our safety. 我们的预防措施保证了我们的安全。
8. 加动词前缀 in-, 使……， insure To cover with insurance vt. 给...保险 You’d better insure your car.你最好给你的汽车买份保险。
9. 加名词后缀 –ance, insurance 保险 I think insurance will be a big business in China.我想保险业会成为中国的一大产业。
10. 加动词前缀a-, assure, vt.断然地说, To cause to feel sure确告, 保证, 担保 The young man assured her of his devotion.那年轻男子让她相信他对她的爱。
另类阅读：
It’s certain that the expensive curtain will be insured. Any possible loss will certainly be met by the insurance company. I’m sure of its certainty.