VOA慢速英语:Laying the Roots for Healthy Teeth in Young Children

2. worsen v. (使)变得更坏,(使)恶化
例句：Already low living standards have been worsened by stringent economic reforms.
严谨的经济改革使本已很低的生活水平愈加恶化。

3. spread vi. 传开;蔓延
例句：The fire spread from the factory to the warehouse nearby.
火从工厂蔓延到了附近的仓库。

4. prevent vt.预防
例句：Vitamin C is supposed to prevent colds.
维生素C可以预防感冒。

5. form v. 形成, 构成, 产生
例句：The idea formed in her mind.
这个想法在她头脑中形成了。

6. swallow vt. 吞, 咽
例句：He put a grape into his mouth and swallowed it whole.
他把一粒葡萄放入嘴里, 整个吞了下去。

7. brush v. 擦; 刷; （用刷子）刷净, 刷亮, 刷平顺
例句：Brush after each meal.
饭后刷牙。

8. supervise v. 监督, 管理
例句：Tomorrow he will supervise all the pupils taking the English examination.
明天全体学生考英语, 他将担任监考。

9. suck v. 吸; 吮
例句：The baby was sucking its mother's breast.
婴儿正在吮吸母乳。

10. advise v. 劝告, 提建议
例句：It is easy for you to advise, but difficult to take advice from others.
劝告别人容易, 接受劝告就难了。