题型:阅读理解 题类:模拟题 难易度:普通
内蒙古阿拉善盟2020届高考英语摸底试卷
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.
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