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阅读短文，回答问题 As the weather gets colder, we start wearing jackets, and most of us stop thinking about the sun. But the sun's rays can be just as harmful when it's cold and cloudy outside. "Any exposed area of your body can still get sunburned, " Dr. Apple A. Bodemer, an assistant professor at the University of Wisconsin-Madison, told Live Science. Whether you spend a day on the slopes or clearing snow out of your driveway, your face is still getting exposed to the sun's radiation in the form of ultraviolet（紫外线）（UV）light, which can go deep into your skin cells, causing DNA damage, according to Bodemer. The sun's long ultraviolet A（UVA）waves can cause earlier aging and wrinkles, while its shorter ultraviolet B（UVB） rays are known for causing skin reddening and bums. Skin damage caused by UV exposure increases over time. More exposure to radiation contributes to severer damage, even skin cancer. In addition, snow and ice can also make sun damage worse. They reflect up to 80 percent of UV rays reaching the ground. That means you get heat from both the sky and the ground. And skiers and snowboarders increase their risk of getting sunburned even more because UV exposure increases at higher altitudes. "Generally, the biggest factor for sun-sensitivity is how pale your skin is," Bodemer said. "But the reality is that even the individual with the darkest skin can get sun damage." Luckily, the solution to protecting your skin is simple：Wear sunscreen every day. Rigel recommended using sunscreen with a sun protection factor（SPF）of at least 30, and that SPFs go higher at higher altitudes. As a rule of thumb, SPF 30 will block 97 percent of UVB rays, SPF 50 blocking 98 percent, and SPF 100 blocking 99 percent. Whatever kind of sunscreen you use, it's important to apply it once about every 2 hours. Rigel also suggested sunscreens with "broad spectrum" - to protect against both UVB and UVA rays - as well as sunscreens that are water-resistant for up to 80 minutes. That way, you can go about your day without it wearing off too quickly. （1） Which of the statements best describes UV light? A . UVB rays cause much less damage to skin than UVA rays. B . Skin damage from UV light can be totally prevented by sunscreen. C . Snow and ice make people suffer much more UV light damage. D . People outdoors needn't worry about getting sunburned on a cold day. （2） Which is the most vital factor as for sun damage? A . Your skin color. B . The clothes you wear. C . The altitude of your place. D . The weather when you are outside. （3） What do we know about sunscreen? A . The lower the sunscreen's SPF is, the better effect it will have. B . People working on high mountains need sunscreen of SPF 30. C . Applying sunscreen once a day when you are outside is necessary. D . Water-resistant sunscreen can be applied once every 80 minutes. （4） What may be the best title for the text? A . Being Exposed to Sun Rays B . Ultraviolet A & Ultraviolet B C . Preventing Sunburn in Winter D . Different Kinds of Sunscreens 答案： C A D C

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