单选题 {{B}}Passage Three{{/B}}
If the population of the Earth goes on increasing at its present rate, there will eventually not be enough resources left to sustain life on the planet. By the middle of the 21 century, if present trends continue, we will have used up all the oil that drives our cars, for example. Even if scientists develop new ways of feeding the human race, the crowded conditions on Earth will make it necessary for us to look for open space somewhere else. But none of the other planets in our solar system are capable of supporting life at present. One possible solution to the problem, however, has recently been suggested by an American scientist, Professor Carl Sagan.
Sagan believes that before the Earth's resources are completely exhausted, it will be possible to change the atmosphere of Venus and so create a new world almost as large as Earth itself. The difficulty is that Venus is much hotter than the Earth and there is only a tiny amount of water there.
Sagan proposed that algae, organisms that can live in extremely hot or cold atmospheres and at the same time produce oxygen, should be bred in conditions similar to those on Venus. As soon as this has been done, the algae will be placed in small rockets. Spaceships will then fly to Venus and fire the rockets into the atmosphere. In a fairly short time, the algae will break down the carbon dioxide into oxygen and carbon.
When the algae have done their works, the atmosphere will become cooler but before man can set foot on Venus, it will be necessary for the oxygen to produce rain. The surface of the planet will still be too hot for men to land on it but the rain will eventually fall and in a few years something like Earth will be reproduced on Venus.
If the experiments are successful, life will become possible there, but it will not be pleasant at first. When they go to Venus, the first colonists will have to take plenty of water with them and get used to days and nights lasting 60 Earth-days. But there will also be some advantages. The colonists will live longer because their hearts will suffer less strain than on Earth. Apart from that, they will be exploiting a new world while those still on Earth are living in closed, uncomfortable conditions. Perhaps it will be the only way to ensure the survival of the human race.
单选题 It will eventually become necessary for us to try to colonize another planet because ______.
【正确答案】 C
【答案解析】[解析] 本题是细节题。文中第一段说得很清楚If the population of the Earth goes on increasing at its present rate…we will have used up all the oil that drives our cars,for example.之所以需要开发另一行星,其根本原因是地球上没有足够的资源来维持人们的生存。故A、B、D均非根本原因,不符合题意。所以C选项是正确答案。
单选题 It is possible for us to colonize Venus immediately for ______.
【正确答案】 C
【答案解析】[解析] 本题是细节题。该题内容出现在文中第二段。Sagan教授认为:困难在于金星的气温比地球高得太多了,以至那儿仅有非常微量的水。所以人类现在没有办法在金星上生存。所以C选项是正确答案。A选项错误因为金星上还是有微量的水资源,B选项不是理由,因为所有的行星都是遥远的,D选项文中没有提及。
单选题 Algae are important for the colonization of Venus since ______.
【正确答案】 B
【答案解析】[解析] 本题是细节题。文中第三段讲Sagan proposed that algae,organisms that can live in extremely hot or cold atmospheres and at the same time produce oxygen,should be bred in conditions similar to those on Venus. 海藻能够在极热或极冷的气候下生存,并且能够产生氧气,而据文章第三段讲:金星上没有氧气,且气候异常,因此将海藻植于金星是非常重要的开发手段,所以B选项是正确答案。A选项根据常识可以排除,C选项不是理由,试想仅能轻易携带而于开发无益的东西有什么用呢?D选项与文章内容不符,海藻不产生二氧化碳。
单选题 The first colonists on Venus will find life difficult there because ______.
【正确答案】 C
【答案解析】[解析] 本题是细节题。A选项文中没有讲到。B选项错误,人们可以带水到金星。C选项讲到金星的白天和黑夜太长。文章最后一段讲,金星的白天和黑夜均有60天之久,对已经习惯12小时左右的白天和黑夜的人们来说,生活在金星上确实有困难,故C选项正确。文章中根本就没有讲到金星上有雨季,何况金星上的水非常少,故D选项是错误的。
单选题 One of the main advantages for colonists will be that ______.
【正确答案】 C
【答案解析】[解析] 本题是细节题。文中并没有说地球上的人们将不复存在,故A选项错误。B选项不是主要的好处,因为地球上的人们也可以将房子装修得很舒适。最后一段讲,在地球上人们生活在拥挤的世界时,金星上的开发者们正在开发一个新的世界,人们在那里生活舒适,所以C选项是正确答案。D选项的内容文章并未提到,他们也许会返回地球,故D选项错。