2014英语四级听力练习慢速4.15(2)_大学英语听力

2014英语四级听力练习慢速4.15(2)

　　Tobacco use is the leading risk factor for causing cancer. The WHO says that tobacco is responsible for over 20 percent of all cancer deaths and 70 percent of all lung cancer deaths. Smoking also causes respiratory diseases, which affect the nose and breathing passages to the surface of the lungs. Respiratory diseases include asthma, bronchitis and emphysema. Smoking can also cause cardiovascular diseases, like heart disease and stroke.

　　People who smoke are not only hurting themselves. They also can harm non-smokers. The WHO officials estimate that secondhand smoke kills 600,000 people each year. It says more than half of the worlds children regularly breathe secondhand smoke.

　　Even after all the warnings, the WHO says over 1 billion people still smoke. The number of smokers is expected to grow, although rates have decreased in the higher income nations.

　　WHO officials say almost 80 percent of all smokers live in low- and middle-income countries. In , the organization said nations in the Western Pacific Ocean have the highest smoking rates. One-third of all smokers live in East Asia and the Pacific. The area has the largest number of male smokers. It also has the fastest-growing number of female and child smokers. Every day, diseases linked to tobacco use kill more than 3,000 people in the area.

　　Scientists have found more than 4,000 chemicals in cigarette smoke. At least 250 of them are known to be harmful. And more than 50 are suspected to cause cancer. They include arsenic, which can be used to kill plants and small animals. Cigarette smoke also contains formaldehyde -- a liquid used to protect the look of dead bodies.