职称英语b级考试之前,我们一定要把历年的真题都做一遍。在这些真题中我们可以学到一些比较重要的知识,这些都是我们在平时训练的时候不知道的。但是,可能很多人都找不到具体的真题,想做一下真题却没有。所以,小编为大家总结了这些真题,我们试着做一下。

Children have an increased of attention problems,seen as early as grade school.If their noses inhaled(吸入)a certain type of air pollution when they were pregnant.That's the finding of a new study.Released when things aren't burned completely,this pollution is known as polycyclic aromatic hydrocarbons,or PAHs.The biggest sources of these PAHs: the burning of fossil fuels,wood and trash.

Frederica Perera works at Columbia University's Mailman School of Public Health is New York City.She researches how exposure to things in the environment affects children's health in a new study,she and her team studied the exposure to air pollution of 233 nonsmoking pregnant women in New York City.Because burning tobacco can spew(排放)PAHs into the air and lungs,Perera's team focused on nonsmokers.The researchers wanted to probe(探查)other sources of PAHs,ones that's would have been hard for an individual to avoid.

The team started by testing the blood of each woman during pregnancy.The reason Any PAHs in a woman's blood would also be available to the baby in her womb.Nine years later,the researchers investigated signs of attention problems in those children,now age 9.They asked each child's mother a series of questions.These included whatever her child had problems doing things that needed sustained(长期的)mental effort,such as homework or games with friends.The scientists also asked if the kids had trouble following instructions or made frequent,careless mistakes.All of these can be symptoms of a disorder called Attention Deficit Hyperactivity Disorder,or ADHD.About one in en has ADHD.

Among the women studied,traffic and home heating were the primary sources of air pollution exposure,Perera and her team suspect.Some of these women had low levels of PAHs in their blood.Ohters had high levels.Those with high levels were five times as likely to have children who showed attention problems by age 9.The new findings were published November 5 in the journal PLOS ONE.

16.Perera and her team chose nonsmoking pregnant women all over America.

A.Right

B.Wrong

C.Not mentioned

参考答案:B

17.The main purpose of the research was to find out how exposure to PAHs played a role in harming the subjects'physical health.

A.Right

B.Wrong

C.Not mentioned

参考答案:B

18.Nonsmoking mothers were selected because the effect of smoking on PAHs was unclear.

A.Right

B.Wrong

C.Not mentioned

参考答案:B

19.The blood of each woman was tested once a month during pregnancy.

A.Right

B.Wrong

C.Not mentioned

参考答案:C

20.Kids with ADHD commonly fail in school.

A.Right

B.Wrong

C.Not mentioned

参考答案:C

21.The women with high levels of PAHs in their blood were more likely to have kids with ADHD.

A.Right

B.Wrong

C.Not mentioned

参考答案:A

22.Traffic and home heating were considered to be the biggest sources of PAHs for the subjects in the research.

A.Right

B.Wrong

C.Not mentioned

参考答案:A