Life in the Universe
Many scientists today are convinced that life exists elsewhere in the universe---life probably much like that on our own planet. They reason in the following way.
As far as astronomers can determine, the entire universe is built of the same matter. They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.
Life requires the right amount and kind of atmosphere. This eliminates all those planets in the universe that are not about the same size and weight as the earth. A smaller planet would lose its atmosphere; a larger one would hold too much of it.
Life also requires a steady supply of heat and light. This eliminates double stars, or stars that flare up suddenly. Only single stars that are steady sources of heat and light like our sun would qualify.
Finally, life could evolve only if the planet is just the right distance from its sun. With a weaker sun than our own, the planet would have to be closer to it. With a stronger sun, it would have to be farther away.
If we suppose that every star in the universe has a family of planets, then how many planets might support life? First, eliminate those stars that are not like our sun. Next eliminate most of their planets; they are either too far from or too close to their suns. Then eliminate all those planets which are not the same size and weight as the earth. Finally, remember that the proper conditions do not necessarily mean that life actually does exist on a planet. It may not have begun yet, or it may have already died out.
This process of elimination seems to leave very few planets on which earthlike life might be found. However, even if life could exist on only one planet in a million, there are so many billions of planets that this would still leave a vast number on which life could exist.
1. Astronomers believe that matter in different parts of the universe
A) has different laws.
B) has one common law.
C) shares the same laws
D) shares no common law.
2. The existence of life depends on all of the following factors EXCEPT
A) the right amount of atmosphere.B) our own solar system.
C) steady heat and light D) the right distance from the sun.
3. Which of the following statements is INCORRECT?
A) The planet must be as big and heavy as the earth.
B) Proper conditions are essential to the existence of life
C) Double stars can provide steady light and heat.
D) The distance between a planet and its sun should be right.
4. What kind of planet might NOT support life?
A) Most of the planets of the stars.
B) Stars similar to our sun.
C) Planets similar to the earth.
D) Planets with proper conditions.
5. At the end of the passage the author suggests that
A) it is impossible for life to exist on planets.
B) earthlike life could only exist on a few planets.
C) life could exist on only one planet in a million.
D) life could exist on a great number of planets.
KEY:CBCAD
名师考试方法精讲之二十三:简短回答题突破经验
名师考试方法精讲之四十八:四级听力高分炼成技巧
名师考试方法精讲之十八:浅谈四级作文
英语考试秘笈:英语四级考试这样过级
名师考试方法精讲之三十七:怎么样提高四级写作水平
名师考试方法精讲之二十六:四级考试听力突破经验
名师考试方法精讲之三十二:高分通过英语四级经验谈
大学英语四级冲刺指导:短期提分秘笈
考试经验介绍:英语四级考试不过的三大原因
名师考试方法精讲之十一:高手背单词经验
名师考试方法精讲之四十二:四级阅读题如何得高分
名师考试方法精讲之十:网考答题技巧
考试经验总结:大学四级考前30天常见问题
名师备课大学四级英语经验精讲之28临阵要磨的五把枪
名师考试方法精讲之三十八:过四级要“阴险”
专家指导:大学生如何准备大学英语四级考试
名师考试方法精讲之四:考试做题窍门
名师考试方法精讲之十五:快速阅读方法
大学英语高分通过四级:功在平时
大学英语考试经验谈:四级备考各阶段注意要点
名师考试方法精讲之四十:大学英语四级学习方法
名师考试方法精讲之八:考试四大板块
名师考试方法精讲之三十三:英语四级考试小经验
名师考试方法精讲之二十二:写作突破经验
名师考试方法精讲之二十九:英语四级听力调整心态重要
名师考试方法精讲之四十三:四级词汇阅读题怎么得高分
名师备课大学四级英语经验精讲:48听力高分策略
名师考试方法精讲之二十:浅谈听力
名师考试方法精讲之六:详解翻译
考友经验秘传:备考英语四级关键要靠执着
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |