1. confine [kən'faɪn] 
vt.限制，禁闭  n. 界限，限制
Cancers are not confined to old people. 癌症不限于老人。

2. refine [rɪ'faɪn] 
vt. 精炼，精制，改善
Crude oil is industrially refined to purify it.原油要经过工业精炼提纯。

3. define [dɪ’faɪn] 
vt. 定义，使明确   definition n. 定义  
definite adj. 一定的，确切的  
infinite adj. 无限的

4. restrict [rɪ’strɪkt] 
vt. 限制 
to restrict the sales of alcohol/guns 限制酒水/枪支的买卖 
Having small children really restricts your social life. 有了孩子真得会限制你的社交。

5. limit [‘lɪmɪt] 
vt. 限制 n. 限制，界线 
high limit 上限
I have to limit my talk to 20 minutes. 我必须把谈话限制在20分钟以内。

6. restrain [rɪ’streɪn] 
vt. 抑制，控制
You should try to restrain your ambitions and be more realistic. 你要试着控制自己的野心，变得现实一些。
Growth in car ownership could be restrained by increasing taxes. 私家车的增长可以通过增加税收进行控制。

7. constrain [kən’streɪn] 
vt. 约束，限制
Rising energy costs are constraining consumer and business spending. 不断上涨的能源成本限制了消费者和企业支出。

8. refrain [rɪ’freɪn] 
vi. 节制，克制
She refrained from making no comment. 她忍住了没做任何评论。

9. curb [kɜːb] 
vt. /n. 控制，勒住 
curb the spread of AIDS 控制艾滋病的蔓延
strict curbs on immigration 对移民的严格控制