Pregnancy and childhood

　　During pregnancy, smoking increases the risk of complications (并发症) that can endanger a mother's life. It nearly doubles the risk of having a low­birth­weight baby. Smoking causes an estimated 910 infant deaths a year, according to the Centers for Disease Control and Prevention. Babies who breathe in second­hand smoke are at increased risk of other problems.

　　Skin

　　If you want to have healthy skin, quit smoking."The nicotine in cigarettes causes narrowing of the blood vessels in the outermost layers of your skin, " says Richard Hurt, director of the Nicotine Dependence Center. "Your skin doesn't get as much oxygen, an important nutrient."He says tobacco contains more than 4, 000 chemicals, many of which can damage fibers that give skin its strength. Quitting improves skin's health and appearance. Smoking also raises the risk of skin cancers.

Welcome to the unit 　　1. Many people die or get ill every day for various reasons. Can you name some?

　　■ diseases,

　　■ natural disasters,_

　　 ■ traffic accidents,

　　■ environment pollution,_

　　■ heavy work pressure,

　　■ lack of exercise and so on.

　　2. Among all these reasons, Aids,_ drinking, drugs and smoking are four main killers.

3. How much do you know about Aids?