In the atmosphere, carbon dioxide acts rather like a one-way mirror—the glass of a roof in a greenhouse which allows the sun’s rays to enter but prevents the heat from escaping.
According to a weather expert’s prediction, the atmosphere will be 3 warmer in the year 2050 than it is today, if man continues to burn fuels at the present rate. If this warming up took place, the ice caps in the poles would begin to melt, thus raising sea level several meters and severely flooding coastal cities. Also, the increase in atmospheric temperature would lead to great changes in the climate of the northern hemisphere, possibly resulting in an alteration of the earth’s chief food-growing zones.
In the past, concern about a man-made warming of the earth has concentrated on the Arctic because the Antarctic is much colder and has a much thinker ice sheet. But the weather experts are now paying more attention to West Antarctic, which may be affected by only a few degrees of warming: in other words, by a warming on the scale that will possibly take place in the next fifty years from the burning of fuels.
Satellite pictures show that large areas of Antarctic ice are already disappearing. The evidence available suggests that a warming has taken place. This fits the theory that carbon dioxide warms the earth.
However, most of the fuel is burnt in the northern hemisphere, where temperatures seem to be falling. Scientists conclude, therefore, that up to now natural influences on the weather have exceeded those caused by man. The question is: Which natural cause has most effect on the weather?
One possibility is the variable behavior of the sun. Astronomers at one research station have studied the hot spots and “cold” spots (that is, the relatively less hot spots) on the sun. As the sun rotates, every 27.5 days, it presents hotter or “colder” faces to the earth, and different aspects to different parts of the earth. This seems to have a considerable effect on the distribution of the earth’s atmospheric pressure, and consequently on wind circulation. The sun is also variable over a long term: its heat output goes up and down in cycles, the latest trend being downward.
Scientists are now finding mutual relations between models of solar-weather interactions and the actual climate over many thousands of years, including the last Ice Age. The problem is that the models are predicting that the world should be entering a new Ice Age and it is not. One way of solving this theoretical difficulty is to assume a delay of thousands of years while the solar effects overcome the inertia of the earth’s climate. If this is right, the warming effect of carbon dioxide might thus be serving as a useful counter-balance to the sun’s diminishing heat.
41. It can be concluded that a concentration of carbon dioxide in the atmosphere would ______.
42. The article was written to explain ______.
43. Although the fuel consumption is greater in the northern hemisphere, temperatures there seem to be falling. This is ______.
44. On the basis of their models, scientists are of the opinion that ______.
45. If the assumption about the delay of a new Ice Age is correct, ______.
问题1选项
A.prevent the sun’s rays from reaching the earth’s surface
B.mean a warming up in the Arctic
C.account for great changes in the climate in the northern hemisphere
D.raise the temperature of the earth’s surface
问题2选项
A.the greenhouse effect
B.the solar effects on the earth
C.the models of solar-weather interactions
D.the cause affecting weather
问题3选项
A.mainly because the levels of carbon dioxide are rising
B.possibly because the ice caps in the poles are melting
C.exclusively due to the effect of the inertia of the earth’s climate
D.partly due to variations in the output of solar energy
问题4选项
A.the climate of the world should be becoming cooler
B.it will take thousands of years for the inertia of the earth’s climate to take effect
C.the man-made warming effect helps to increase the solar effects
D.the new Ice Age will be delayed by the greenhouse effect
问题5选项
A.the best way to overcome the cooling effect would be to burn more fuels
B.ice would soon cover the northern hemisphere
C.the increased levels of carbon dioxide in the atmosphere could warm up the earth even more quickly
D.the greenhouse effect could work to the advantage of the earth
第1题:D
第2题:D
第3题:D
第4题:A
第5题:D
第1题:
推理判断题。题干意思是“可以得出结论的是，大气中二氧化碳的浓度将会……”。根据文章第一段carbon dioxide acts rather like a one-way mirror—the glass of a roof in a greenhouse which allows the sun’s rays to enter but prevents the heat from escaping.（二氧化碳的作用就像一面单向镜子——温室屋顶的玻璃，它允许阳光进入，但阻止热量逸出。）可知A项“阻止太阳光线到达地球表面”，内容与文章内容相反；B项“意味着北极的气候变暖”，第三段最后两句提到But the weather experts are now paying more attention to West Antarctic, which may be affected by only a few degrees of warming: in other words, by a warming on the scale that will possibly take place in the next fifty years from the burning of fuels.（但是，气象专家现在把更多的注意力放在了南极西部，那里可能只会受到几度的变暖的影响：换句话说，由于燃料的燃烧，在未来的50年里可能会出现这样的变暖），由此可知，现在南极气温更容易受气候变暖的影响，所以B项内容不准确；C项“导致了北半球气候的巨大变化”，内容与原文所说正相反，第五段第一句提到However, most of the fuel is burnt in the northern hemisphere, where temperatures seem to be falling.（然而，大部分燃料是在北半球燃烧的，那里的气温似乎正在下降），由此可知二氧化碳会使大气温度上升，但事实上气温却在降低，所以是无法用二氧化碳来解释北半球气温变化的，C项错误；根据第四段最后两句话The evidence available suggests that a warming has taken place. This fits the theory that carbon dioxide warms the earth.（现有的证据表明气候已经变暖。这符合二氧化碳使地球变暖的理论。）可知D项“提高地球表面的温度”符合题意。因此该题选D。
第2题:
推理判断题。题干意思是“文章是用来解释……”。从全文来看，作者主要探讨了两种对大气温度变化产生影响的原因——人为因素和自然因素。若以人为原因为主，现在的大气温度应比以前更高，但事实上相反，大气温度似乎在下降；若以自然原因为主，现在应该进入一个新的冰河时代，但是又没有，说明二氧化碳与太阳在相互影响着大气的温度，只有D项“影响天气的原因”全面表达了文章的内容，即解释影响天气的原因。A项“温室效应”和B项“太阳对地球的影响”都只是其中一个原因，不够全面。C项“太阳-天气相互作用的模型”太片面，也不选。因此该题选D。
第3题:
推理判断题。题干意思是“虽然北半球的燃料消耗较大，但那里的气温似乎在下降。这是……”。根据题干定位到文章的第五段第二句Scientists conclude, therefore, that up to now natural influences on the weather have exceeded those caused by man. （因此，科学家得出结论，到目前为止，自然对天气的影响已经超过了人类造成的影响），接着作者在第六段提到One possibility is the variable behavior of the sun....its heat output goes up and down in cycles, the latest trend being downward.（一种可能是太阳的变化……它的热量输出呈周期性上升和下降，最新的趋势是下降），由此可知，影响北半球气温下降的原因有一部分是自然的影响，因此D项“部分原因是太阳能输出的变化”符合题意。A项“主要是因为二氧化碳的含量在上升”，第七段提到If this is right, the warming effect of carbon dioxide might thus be serving as a useful counter-balance to the sun’s diminishing heat.（如果这是正确的，那么二氧化碳的变暖效应可能会起到有效的平衡太阳热量递减的作用），由此可知，大气中不断上升的二氧化碳浓度能平衡气温中不断消失的太阳热量，所以A项内容不正确；B项“可能是因为两极的冰盖正在融化”，与题干无关；C项“这完全是由于地球气候惯性的影响”，内容太绝对。因此该题选D。
第4题:
事实细节题。题干意思是“根据他们的模型，科学家们认为……”。根据文章的第七段的第二句话…that the models are predicting that the world should be entering a new Ice Age（这些模型预测世界将进入一个新的冰河时代，但事实并非如此），由此可知科学家认为气候应该变得更冷，因此A项“世界的气候应该会变得更冷”符合题意。B项“地球气候的惯性将需要数千年才能起作用”，最后一段倒数第二句One way of solving this theoretical difficulty is to assume a delay of thousands of years while the solar effects overcome the inertia of the earth’s climate.（解决这一理论难题的一种方法是假设有数千年的延迟，而太阳效应克服了地球气候的惯性），根据这个句子可知文章提到太阳效应克服地球气候的惯性是用来对科学家们认为的模型预测世界将进入一个新的冰河时代的一种假设，不符合题意；C项“人为的变暖效应有助于增加太阳效应”，文章最后一句提到the warming effect of carbon dioxide might thus be serving as a useful counter-balance to the sun’s diminishing heat.（二氧化碳的变暖效应可能会起到有效的平衡太阳热量递减的作用），因此C项错误。D项“新的冰川期将被温室效应推迟”，文章中科学家做出的假设是太阳效应克服了地球气候的这种惯性，所以D项错误。因此该题选A。
第5题:
推理判断题。题干意思是“如果新冰河世纪延迟的假设是正确的，那么……”。文章最后两句话提到One way of solving this theoretical difficulty is to assume a delay of thousands of years while the solar effects overcome the inertia of the earth’s climate. If this is right, the warming effect of carbon dioxide might thus be serving as a useful counter-balance to the sun’s diminishing heat.（解决这一理论难题的一种方法是假设有数千年的延迟，而太阳效应克服了地球气候的惯性。如果这是正确的，那么二氧化碳的变暖效应可能会起到有效的平衡太阳热量递减的作用），可知如果新冰河世纪延迟的假设是正确的，温室效应可以平衡太阳热量递减的作用，因此对地球是有利的，这与D项“温室效应可能对地球有利”符合；A项“克服这种冷却效应的最好方法是燃烧更多的燃料”原文未提及；B项“冰很快就会覆盖北半球”，第五段首句提到most of the fuel is burnt in the northern hemisphere（大部分燃料是在北半球燃烧的），所以B项内容不正确；C项“大气中二氧化碳含量的增加会使地球更快地变暖”，不是变暖，而是平衡太阳热量的递减，C项也不正确。因此该题选D。
