Haveyouevergottenasunburn?Ifyouhave,you’vealreadylearne...
问题详情:
Have you ever gotten a sunburn? If you have, you’ve already learned the hard way about the sun’s ultraviolet (紫外线的), or UV light. It can burn your skin so bad that it turns it red or even makes it peel off. The 51 helps you remember to wear sunscreen the next time.
Well, Earth has its own version of sunscreen, the ozone (臭氧) layer, which 52 us all from the vast majority of the UV light released by the sun. Without it, we wouldn’t just get a sunburn. Life on Earth would go 53 due to the hugely damaging power of all those UV rays.
The ozone layer 54 Earth’s stratosphere (同温层), a part of the atmosphere that 55 from about 10 kilometers up to nearly 50 kilometers above the ground. Despite its name, the ozone layer isn’t just ozone gas. It contains relatively higher concentrations of ozone than the lower atmosphere, but that’s still a small amount 56 those of the main elements of the atmosphere. Even so, it 57 a lot of UV rays, preventing them from reaching the surface of Earth.
However, people weren’t fully aware of its importance until 1985, when a huge hole in the layer was found over Antarctica.
The 58 quickly pointed to a kind of chemical called chlorofluorocarbon, or CFC, which was widely used in refrigerators, air conditioners and hairsprays. CFCs are able to rise up to the stratosphere and cause reactions that destroy ozone. With a 59 ozone layer, people on Earth are more likely to develop skin cancer, cataracts (白内障) and other health problems due to too much UV light 60 .
As a result of this discovery, an international treaty (条约) called the Montreal Protocol was signed in 1987 to 61 the manufacture of CFC products so that the ozone layer could slowly recover and return to its natural state by 2050.
62 , at a time when it seemed that everything was going back to 63 , earlier this month scientists detected four new man-made gases in Greenland and Australia that could causes new risks to the ozone layer.
Scientists haven’t identified the 64 of the gases, but “this highlights that ozone loss is not yet yesterday’s story,” said Professor Piers Forster from the University of Leeds, UK, to BBC. Scientists believe that there are more such gases out there, and they still have much work to do to “ 65 the holes”.
51. A. harm | B. loss | C. pain | D. factor |
52. A. survives | B. shades | C. prevents | D. covers |
53. A. extinct | B. helpless | C. meaningless | D. wrong |
54. A. links to | B. lies in | C. looks to | D. consists of |
55. A. receives | B. locates | C. extends | D. varies |
56. A. belonged to | B. turned to | C. taken to | D. compared to |
57. A. absorbs | B. captures | C. figures | D. imposes |
58. A. result | B. evidence | C. trace | D. movement |
59. A. further | B. clearer | C. thinner | D. broader |
60. A. return | B. exposure | C. companion | D. approach |
61. A. ban | B. oppress | C. motivate | D. recycle |
62. A. Therefore | B. Furthermore | C. Otherwise | D. However |
63. A. minor | B. bitter | C. concrete | D. normal |
64. A. source | B. guidance | C. condition | D. destination |
65. A. fasten | B. heighten | C. tighten | D. strengthen |
【回答】
CBABC DABCB ADDAC
知识点:健康保健类
题型:完型填空
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下列说法正确的是 A.物质发生化学反应都伴随着能量变化B.伴有能量变化的物质变化都是化学变化C.在一个确...
问题详情: 下列说法正确的是 A.物质发生化学反应都伴随着能量变化B.伴有能量变化的物质变化都是化学变化C.在一个确定的化学反应关系中,反应物的总能量总是高于生成物的总能量D.放热反应的发生无需任何条件【回答】A知识点:化学反应中的能量变化题型:选择题...
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某商品进价是1000元,售价为1500元.为促销,商店决定降价出售,但保*利润率不低于,则商店最多降 元...
问题详情:某商品进价是1000元,售价为1500元.为促销,商店决定降价出售,但保*利润率不低于,则商店最多降元出售商品.【回答】450元. 知识点:一元一次不等式题型:解答题...
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用若干个体积为1的正方体搭成一个几何体,其正视图、侧视图都是如图所示的图形,则这个几何体的最大体积与最小体积的...
问题详情:用若干个体积为1的正方体搭成一个几何体,其正视图、侧视图都是如图所示的图形,则这个几何体的最大体积与最小体积的差是()A.2B.3C.4D.5【回答】解析:由正视图、侧视图可知,此几何体的体积最小时,底层有5个小正方体,上面有2个小正方体,共7个小正方体;体积最大时,底...
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可吸入颗粒物(指空气动力学直径小于10微米的颗粒物,表示为PM10。PM2.5是指大气中直径小于或等于2.5微...
问题详情:可吸入颗粒物(指空气动力学直径小于10微米的颗粒物,表示为PM10。PM2.5是指大气中直径小于或等于2.5微米的颗粒物,也称为可入肺颗粒物)是*市大气的一种主要污染物,它们虽然在大气中的含量很少,但是它对环境和人体的危害都很大。回答3-4题。3.读*市2003年1月16...
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