题目内容
During the past week, Beijing has been covered with thick smog that is forecast to stay until this weekend at least.
The smog, covering 1.43 million square kilometers mainly in northern China, made the Beijing government give an orange alert - the second-highest warning - and ordered people not to leave their homes.
A study in 2013 by researchers at Tsinghua University said that there were more than 1,300 microbes(可吸入颗粒) in the atmosphere over Beijing. Although most of them may do no harm to human health, the number still makes people worried.
Zhuang Guoshun, director of the Center for Atmospheric Chemistry Study at Fudan University, said Beijing is covered by smog for an average of 60 percent of the year, while the number for Shanghai is 30 to 50 percent.
However, research studies have found that higher air pollution levels do not exactly mean higher risks of early death or other health illnesses.
One of the scientists' main attentions is the level of PM2.5 - floating matter of 2.5 microns (微米)or smaller, which can go deep into the lungs(肺) and even enter the blood.
Guangzhou and Shanghai in the south of China have slightly higher relative risks to early death from the effects of PM2.5 than Xi'an and Beijing in the north, even though the levels of PM2.5 in the northern cities were nearly twice those in the south, according to a study published in September 2013, led by Pan Xiaochuan, a professor at Peking University's School of Public Health.
1.What colour warning is the second-highest one?
A. Blue. B. Orange. C. Red. D. Black.
2.The third paragraph mainly tells us that __________．
A. the number of microbes worries people B. smog does no harm to our health
C. the professor is from Fudan University D. Beijing must pay attention to the pollution now
3.According to the fourth paragraph, we can see that in a year Shanghai is covered with smog at least __________ days.
A. 73 B. 110 C. 146 D. 183
4.Which city has a little higher relative risk to early death from PM 2.5?
A. Xi’an B. Beijing C. Nanjing D. Guangzhou
1.B 2.A 3.B 4.D 【解析】短文报道了在过去的一周里，北京上空一直笼罩着雾霾。清华大学研究人员在2013年进行的一项研究表明，北京上空的大气中有1300多种可吸入微生物，虽然它们中的大多数对人体健康没有危害，但这个数字仍然让人担忧。然而，研究发现，较高的空气污染水平并不意味着早死或其他健康疾病的风险更高。在PM 2.5相同的情况下，南方的城市早期死亡相对风险更高...
B. 
C. 