题目

阅读理解 Breathing dirty air can cost someone's lifespan (寿命) months—even years, a new study finds. Worldwide, air pollution lowers average lifespans by a year. Scientists shared their new findings in Environmental Science & Technology Letters. Air pollution (污染) has been linked to many health problems. Most earlier studies have looked at how tiny air pollutants affected rates of illness or death. But now an environmental scientist, Joshua Apte, is going even further. He works at the University of Texas, Austin. He together with his team is looking at life expectancy, hoping to make the threat easier to understand. PM 2.5 is what scientists call tiny particles of pollution in the air. Higher levels of PM2.5 can cause health problems and cut months, if not years, from the average lifespan. This analysis shows pollution affects life expectancy in different parts of the world. The World Health Organization (WHO) recommends limiting PM 2.5 to 10 micrograms (微克) per cubic (立方) meter of air. Apte's group used data to try to find how this low level would help people. But meeting the WHO standard won't get rid of health damage from dirty air. That's because even below 10 micrograms per cubic meter pollution still causes huge risks. Reducing air pollution could increase life expectancy. The scientists also compared how other threats shorten life spans across the globe. These risk factors included smoking and cancer. These results show that in poor countries, cleaning up dirty air could greatly increase lifespans. It could have as big an effect as cleaning up drinking water, or curing lung cancer. However, in wealthier countries air pollution shortens life expectancy by less than half a year. All forms of cancer, in fact, shorten the average life expectancy by more than 3.5 years. "Knowing this can really help people. or policymakers, decide where to spend their money." says Kirk Smith. （1） Why is Joshua Apte's team carrying out the study? A . Know how small air pollutants are. B . Study many different healthy problems. C . Study the life expectancy of different people. D . Let people understand air pollution better. （2） What will happen if one country limits PM 2.5 to 10 micrograms per cube meter? A . Its air is very clean. B . It will get a prize from WHO. C . It still has pollution risks. D . Its people will live a healthy life. （3） What can we infer from the last paragraph? A . The study will help different countries or people take different policies. B . Lung cancer is the leading killer in all kinds of cancers. C . Reducing air pollution can increase all people's lifespans much. D . It's very hard to clean up dirty air in a short time. （4） What can be the best title for the text? A . Many Factors are Affecting People's Health B . Air Pollution is Shortening Lives Worldwide C . Governments are Trying to Make Lifespan Long D . The Effect of Cancer is Worse than Dirty Air 答案： D C A B

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