1. Today cigarette smoking is a widespread habit all over the world. 2. It is the single biggest avoidable cause of death and disability in developed countries. 3. Americans smoke 6 billion cigarettes every year. 4. In the United Kingdom there are about 13 million smokers. 5. In China, 35% above the age of 15 are smokers. 6. There are 6.5 billion people in the world, and about 1.2 billion of them are smokers, which make up to 20% of the world’s total population. 7. Therefore， many countries have worked out laws forbidding smokers to smoke in public places such as cinemas， hospitals and stations. 8. It's a very serious problem because not only the old， the youth， but also middle school students and girls have been engaged in smoking. 9. We meet smokers everywhere.

1. Many heavy smokers say they cannot leave off， although they know smoking is harmful to their health. And they have tried again and again to stop. 2. In their view, smoking is very interesting. 3. Even more people think smoking can relax them when they are under pressure.

1. However in the smoke there are many harmful sustains such as nicotine(尼古丁) carbon monoxide and so on . 2. Nicotine included in a smoke can kill a mouse and twenty smokes can kill a cattle. 3. You can calculate how many you had been smoking and calculate how many mice or cattle you had killed.

1. The poisonous gas from smoking is one of the major causes of many kinds of diseases. 2. Those who smoke too much may not live long. 3. First, the most serious one is lung cancer and smoking also affects the heart and blood vessels. 4. Second, cigarette smoking is an important factor in the development of cancer of the throat and related to cancer of the bladder and the oral cavity. 5. In addition, smokers have a higher death rate from heart