Question

    Some people sit outside for hours without getting bitten by mosquitoes, but it always seems like you’re being eaten alive within minutes of stepping outdoors.

If this is you, you’re not alone. According to Smithsonian Magazine, around 20 percent of people in the world are especially tasty to mosquitoes. What about these people makes mosquitoes’ mouths water?

A popular myth claims that mosquitoes prefer certain blood types, but the fact is that they simply can’t tell what your blood type is from a faraway place. Jonathon Day, a professor of medical entomology (昆虫学) at the University of Florida in the US, told NBC it’s not complicated. “The two most important reasons a mosquito is attracted to you have to do with sight and smell.”

Mosquitoes are especially active in the late afternoon. While flying along, they use their sense of smell to find possible targets. They find victims (攻击对象) by smelling the carbon dioxide (CO²) breathed out by humans and animals. That’s why you commonly find them in crowded streets and parks.

Joop van Loon, an entomologist at Wageningen University in the Netherlands, told Live Science, “Mosquitoes start orienting (使......朝向) themselves to carbon dioxide and keep flying upwind as they sense higher concentrations (浓度).”

As a result, people who simply exhale (呼出) more of the gas over time – generally, larger people – have been shown to attract more mosquitoes than others. “This is why kids don’t get bitten as much ... as adults,” US professor Ted Rosen told Science Alert.

This love for CO² can also put pregnant women at increased risk for mosquito bites, as they tend to exhale 21 percent more CO² than people of the same age and size who aren’t pregnant.

In addition to carbon dioxide, the color of the clothes you wear also plays a role in attracting mosquitoes.

According to Live Science, mosquitoes can lock onto targets from up to 50 meters away. At this distance, what we wear has a huge effect. Due to their vision (视觉), people wearing dark colors are more likely to become targets.

Being bitten by mosquitoes is annoying, but don’t worry. Some simple tips can help ward them off. Scientists recommend that we use insect repellent (驱虫剂) and wear light-colored clothing.

1.How do mosquitoes locate their targets, according to the article?

A.By seeking out bright clothes.

B.By identifying different blood types.

C.By sensing an increase of carbon dioxide.

D.By following bigger crowds.

2.Why are pregnant women more likely to be bitten by mosquitoes?

A.Their larger size helps mosquitoes to see them.

B.They breathe out more CO².

C.They are more likely to sweat.

D.Their body temperatures are higher.

3.How does the article advise you to avoid mosquitoes?

A.Exercise regularly.

B.Wear light-colored clothing.

C.Keep your skin dry and clean.

D.Stay indoors in the evening.

4.What’s the article mainly about?

A.A new finding about mosquitoes.

B.How people can avoid mosquito bites.

C.A popular myth about mosquitoes.

D.Why some people are more attractive to mosquitoes than others.

Answer

1.C

2.B

3.B

4.D

【解析】

这是一篇说明文。文章向读者介绍了为什么有些人可以整个夏天坐在户外乘凉却不被蚊子叮咬，而有些人一出门就好像要被蚊子吃掉一样。

1.细节理解题。由文章第四段中的“While flying along, they use their sense of smell to find possible targets. They find victims by smelling the carbon dioxide (CO2) breathed out by humans and animals. （飞的时候，它们用嗅觉发现目标。它们通过闻人和动物呼出的二氧化碳来锁定目标。）”与第五段中的“Mosquitoes start orienting themselves to carbon dioxide and keep flying upwind as they sense higher concentrations（蚊子开始飞向有二氧化碳的地方，当它们感知到高浓度的二氧化碳时，就保持逆流飞行）”可知，蚊子通过感知二氧化碳的增加来锁定目标。故选C。

2.细节理解题。由第七段内容：This love for CO2 can also put pregnant women at increased risk for mosquito bites, as they tend to exhale 21 percent more CO2 than people of the same age and size who aren’t pregnant. （对二氧化碳的喜欢使得孕妇很容易被蚊子咬，因为她们比正常相同年龄，相同体型的人呼出多余21%的二氧化碳），可知，孕妇呼出更多的二氧化碳，所以更招蚊子咬。故选B。

3.细节理解题。由文章最后一段中的“Scientists recommend that we use insect repellent and wear light-colored clothing.（科学家建议我们使用驱虫剂或者穿浅颜色的衣服。）”可知，文章建议我们可以通过穿浅色衣服来避免蚊子叮咬。故选B。

4.主旨大意题。由文章第二段中的“According to Smithsonian Magazine, around 20 percent of people in the world are especially tasty to mosquitoes. What about these people makes mosquitoes’ mouths water?（根据Smithsonian杂志，世界上大约20%的人容易招蚊子咬。为什么这些人非常吸引蚊子呢？）”可知，本文探讨的话题是：为什么一些人比其他人更容易招蚊子。故选D。