Question

    One of the most dangerous insects you need to watch out for during summer is mosquitoes. But no matter how you try to avoid them, some people naturally attract mosquitoes more than others.

One of the most important facts to remember is that mosquitoes track people down by smell and body odour(气味), according to Bart Knols, PhD, a biologist devoted to the study of mosquitoes. The carbon dioxide people breathe out, along with chemicals from the skin, creates an “odour plume” that mosquitoes can detect from up to almost 100 feet away. “Each person gives off more than 300 chemicals from the skin, more than 100 in breathing out,” Knols says.

The specific mixtures on the skin that mosquitoes respond to vary by species. The yellow fever mosquito and Asian tiger mosquito, for example, respond well to lactic acid from skin. African malaria mosquitoes respond to a mix of fatty acids, according to Knols. Your individual mixtures and smells determine how much of a mosquito attraction you are, depending on the mosquito species. The mix of chemicals you produce are only partly in your control. These chemicals depend on your genetic make-up, health condition, diet, skin pH, and so on. “Bacteria(细菌)on the skin break down the mixtures that we give off through our pores(毛孔), and these are the attractive smells,” Knols says. “So it is not actually we that attract mosquitoes, but the bacteria on our skin.”

Although this is a complex and partly understood phenomenon, Knols says that we do all have a unique smell. There are many folk stories about why some people are more or less attractive to mosquitoes. Some people falsely think the blood type is the cause, and others believe taking vitamin B or eating garlic makes people less attractive to mosquitoes—but Knols notes there’s no scientific data backing these claims.

1.What do we learn from the second paragraph?

A.Mosquitoes can detect people with smell. B.Nobody can avoid mosquitoes anyway.

C.A person breathes out over 300 chemicals. D.People naturally attract mosquitoes.

2.Why does the author take several kinds of mosquitoes for example?

A.To persuade readers to protect the environment.

B.To warn people against touching mosquitoes.

C.To show different mosquitoes react to mixtures.

D.To make people look out for poisonous mosquitoes.

3.What draws mosquitoes according to Bart Knols?

A.Chemicals in the mouth. B.Mixtures people give off.

C.Smells from the pores. D.Bacteria on the skin.

4.What is the best title for the text?

A.The Scientific Reason You Are a Mosquito Attraction

B.Folk Stories about How Mosquitoes Attack People

C.Attitudes toward Mosquitoes Different People Have

D.Ways to Make People More and More Attractive

Answer

1.A

2.C

3.D

4.A

【解析】

这是一篇说明文。文章介绍了蚊子追踪人们的嗅觉和体味，人的皮肤会产生很多不同的物质，而不同的蚊子对皮肤的不同物质反应不同。

1.

细节理解题。根据第二段的One of the most important facts to remember is that mosquitoes track people down by smell and body odour(气味), according to Bart Knols, PhD, a biologist devoted to the study of mosquitoes. 据专门研究蚊子的生物学家Bart Knols博士说，要记住的最重要的事实之一是蚊子通过气味和体味来追踪人。可知，蚊子可以通过气味探测人。故选A。

2.

推理判断题。根据第三段的The specific mixtures on the skin that mosquitoes respond to vary by species. 蚊子对皮肤上的特定混合物有反应，这种混合物因物种而异。可知，下文列举黄热病蚊子和亚洲虎蚊及非洲疟疾蚊子是为了表明不同的蚊子对不同的混合物反应不同。故选 C。

3.

细节理解题。根据第三段的 Knols says. “So it is not actually we that attract mosquitoes, but the bacteria on our skin.”Knols说。“所以实际上吸引蚊子的不是我们自己，而是我们皮肤上的细菌。”可知，吸引蚊子的是皮肤上的细菌。故选D。

4.

主旨大意题。文章介绍了蚊子追踪人们的嗅觉和体味，人的皮肤会产生很多不同的物质，而不同的蚊子对皮肤的不同物质反应不同。我们之所以吸引蚊子是因为我们皮肤上的细菌。因此，选项A“你吸引蚊子的科学原因”是本文的最佳标题。故选A。