The hole in the earth's protective ozone layer（臭氧层）won't repair itself until about two decades later than had been expected, scientists announced.
The ozone layer blocks more than 90 percent of the sun's ultraviolet radiation（紫外线辐射）, helping to make life on Earth possible. For many dacades, ozone was depleted（削减） by chlorine and bromine gas in the air. A hole in the ozone layer formed over the Southern Hemisphere.
Computer models had forecast that the hole would fill back in by 2050. An improved puter model forecasts the recovery won't occur until 2068. The model, fed with fresh data from statellites and airplanes, was supported by the fact that it accurately reproduced ozone levels in the Antarctic stratosphere（平流层）over the past 27 years.
The ozone hole is actually more of a broad region with less ozone than ought to occur naturally. It is not limited to Antarctica, as is often believed.
Over areas that are farther from the poles like Africa or the US, the levels of ozone are only three to six percent below natural levels. Over Antarctica, ozone levels are 70 percent lower in the spring. This new method allows us to more accurately estimate（估计）ozone-depleting gases over Antarctica, and how they will decrease over time, reducing the ozone hole area.
Paul Newman, a scientist,said that the ozone hole has not started to bee smaller as quickly as expected. They figure it will not bee much smaller until 2018, after which time the recovery should proceed more quickly. And the hole will not be filled in again until 2065.
【小题1】According to the passage, the ozone layer A．absorbs as much as sunlight as possibleB．protects man against ultraviolet radiationC．controls the changes in temperatureD．prevents the production of carbon dioxide【小题2】The improved puter model is believable because A．it was once proved by factsB．it has been studied for 27 yearsC．it was created by many scientistsD．it is related to satellites and airplanes【小题3】The underlined word “they” in the fifth paragraph refers to A．the levels of ozoneB．ozone-depleting gasesC．the ozone holesD．the areas far from the polesB
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(答案→)B
解析：
【小题1】B 细节题。根据第二段1,2行The ozone layer blocks more than 90 percent of the sun's ultraviolet radiation（紫外线辐射）, helping to make life on Earth possible.说明B正确。
【小题2】A 细节题。根据第三段2,3，4行The model, fed with fresh data from statellites and airplanes, was supported by the fact that it accurately reproduced ozone levels in the Antarctic stratosphere（平流层）over the past 27 years.说明该模型在过去的27年中得到了证明，故A正确。
【小题3】B 推理题。根据本句This new method allows us to more accurately estimate（估计）ozone-depleting gases over Antarctica, and how they will decrease over time, reducing the ozone hole area.
说明这里的they是指ozone-depleting gases，故B正确。