参考译文
天文学方面的最新发展使得我们能够在银河系和其他星系发现行星。这是一个重要的成就，因为相对来说，行星很小，而且也不发光。寻找行星证明相当困难，但是要在行星上发现生命会变得无比艰难。第一个需要解答的问题是一颗行星是否有能够维持生命的条件。举例来说，在我们的太阳系里，对于生命来说，金星的温度太高，而火星的温度则太低。只有地球提供了理想的条件，而即使在这里，植物和动物的进化也用了40亿年的时间。
一颗行星是否能够维持生命取决于它的恒星——即它的“太阳”——的大小和亮度。设想一下，一颗恒星比我们的太阳还要大，还要亮，还要热20倍，那么一颗行星为了维持生命就要离它的恒星非常远。反之，如果恒星很小，维持生命的行星就要在离恒星很近的轨道上运行，而且要有极好的条件才能使生命得以发展。但是，我们如何才能找到这样一颗行星呢？现在，没有一台现存的望远镜可以发现生命的存在。而开发这样一台望远镜将会是21世纪天文学的一个重要的研究课题。
使用放置在地球上的望远镜是无法观察到其他行星上的生命的。地球周围温暖的大气层和望远镜散出的热量使得我们根本不可能找到比行星更小的物体。即使是一台放置在围绕地球的轨道上的望远镜——如非常成功的哈勃望远镜——也因为太阳系中的尘埃微粒而无法胜任。望远镜要放置在木星那样遥远的行星上才有可能在外层空间搜寻生命，因为我们越是接近太阳系的边缘，尘埃就越稀薄。一旦我们找到这样一颗行星，我们就要想办法将它的恒星射过来的光线遮暗，这样我们就能彻底“看见”这颗行星，并分析它的大气层。首先我们要寻找植物，而不是那种“小绿人”。在行星上最容易生存下来的是细菌。正是细菌生产出我们在地球上呼吸的氧气。在地球发展的大部分进程中，细菌是地球上唯一的生命形式。作为地球上的居民，我们总存有这样的希望：小绿人来拜访我们，而我们可以和他们交流。但是，这种希望总是只在科幻小说中存在。如果我们能够在另一颗行星上找到诸如细菌那种低等生命，那么这个发现将彻底改变我们对我们自已的看法。正如美国国家航空和宇宙航空局的丹尼尔·戈尔丁指出的：“在其他地方发现生命会改变一切。任何人类的努力和想法都会发生变化。”
Comprehension
理解
Give short answers to these questions in your own words as far as possible. Use one complete sentence for each answer.
1Why is it a major achievement to be able to find new planets in space?
2Why can't all planets support life?
3What will be one of the great astronomical projects of the twenty-first century?
Vocabulary
词汇
Explain the meanings of the following words and phrases as they are used in the passage: detect (1. 1); in relative terms (1. 3); emit (1. 4); ideal conditions (1. 8); capable of (1. 12); alternatively (1. 12); presence (1. 15).
Summary writing
摘要写作
In not more than 80 words describe what would have to be done to find life on a distant planet and what kind of life this might be. Do not include anything that is not in the last paragraph.
Composition
作文
Write a Composition in about 300 words on one of the following:
aExtra terrestrials.
bSupposing the time came when we could send pictures of life on earth to intelligent creatures on other planets. What sorts of pictures do you think would be most interesting to them?
Letter writing
书信写作
You borrow from a friend a travel guide which you are now returning. Write him or her a letter of about 100 words thanking him or her for having lent it to you and saying how useful you found it.
Key structures and Special difficulties
关键句型和难点
Rewrite the following sentence without changing the meaning. Then refer to 11. 20-21.
A telescope would have to be far away ---- for instance round the planet Jupiter ---- to look for life in outer space. A telescope would…as the planet Jupiter……
Multiple choice questions
多项选择题
Choose the correct answers to the following questions.
Comprehension 理解
1Why are planets in other solar systems so much more difficult to detect than stars?
a．Because of the dust particles in our own solar system.
b．Because of the limitations of earth-based telescopes.
c．Because even the Hubble is not powerful enough to see beyond the Milky Way.
d．Because planets are small and dark, and stars are large and radiant.
2What do we know about the kind of planet, other than our own, that might be able to support life?
a．It will orbit closely round its star.
b．It will be at least four billion years old.
c．Its distance from its star will be such that it has a moderate temperature.
d．It will have an atmosphere capable of supporting bacteria.
3A telescope capable of finding life on other planets would have to be
a．far enough from the centre of our solar system not to be affected by dust
b．infinitely more powerful than even the very successful Hubble
c．orbiting in a different solar system a long way away from our own
d．on the planet Jupiter, on the edge of our solar system
Structure 结构
4It has become possible ______ recent developments in astronomy to…(1. 1)
a．caused by
b．through
c．as regards
d．for
5Venus is far too hot and Mars is too cold ______ there to be any life. (11. 7-8)
a．than
b．whether
c．for
d．nor
6A planet would have to be a very long way from ______ (11. 11-12)
a．so big a star
b．such big star
c．a like star
d．a star as this
7At present, the telescope ______ that is capable of detecting life. (11. 14-15)
a．does not exist
b．no exist
c．cannot exist
d．won't exist
8______ in human endeavour or thought would be unchanged. (11. 30-31)
a．All things
b．Everything
c．Nothing
d．NoneVocabulary
词汇
9Imagine a star ______ twenty times larger than our own sun. (11. 10-11)
a．as much as
b．as well as
c．such as
d．as if
10The oxygen we breathe
on earth has been ______ by bacteria. (11. 25-26)
a．manufactured
b．fabricated
c．produced
d．given being
11As Earth-dwellers, we ______ that we will be visited by little green men. (11. 26-27)
a．like to know
b．fondly dream
c．love to expect
d．profoundly believe
12No human endeavour or thought would be ______ by it. (11. 30-31)
a．unaltered
b．ineffective
c．unchallenged
d．unchecked |
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