Question

When we look at the sky and see a bright light moving quickly across it or coming towards the earth, we talk about seeing a “shooting star” or a “falling star”. These moving lights are not, in fact, stars at all. They are small pieces of matter from outer space, which burn up as they enter the Earth’s atmosphere. The correct name of them is meteoroids. Any pieces that make it to the Earth’s surface without completely burning up are known as meteorites. A meteor is actually the name given to the light we see when a meteoroid is burning up.
When a meteorite hits the Earth at speeds between 11 and 72 kilometers a second, it can do amazing damage. A very large meteorite could knock the earth out of its orbit. If this happened, all life on Earth would probably become extinct（灭绝）. The path we follow around the Sun would change and as a result the Earth would become either much hotter or much colder. This change in temperature would affect sea levels and the amount of water in rivers. There would either be huge floods, which would cover most of the land with water, or the oceans would dry up and there would be a drought, which means a long period of time without rain. Either way, nothing could survive. If a large meteorite landed in the sea it would almost certainly cause tsunamis, which would race towards the land, destroying everything in their paths.
Although it is unlikely the Earth will be struck by a meteorite large enough to do that kind of damage, there is evidence of fairly large meteorites hitting the Earth in the past. In 1908 a large area of forest in Tunguska, Siberia was destroyed by a meteorite that came apart just before it hit the ground. The moon, however, has about three billion craters陨石坑caused by meteorites impacting影响 its surface. The reason more meteorites have reached the surface of the moon than the surface of the Earth is that the moon does not have enough atmosphere for the meteorites to burn up in. some of the meteorites that have reached the Earth’s surface have done considerable damage. Some scientists believe it was a change of climate caused by meteorites hitting the Earth that resulted in the extinction of the dinosaurs and other large prehistoric animals.
Scientists are especially interested in meteorites because they contain information about the solar system. It is widely believed by scientists that most meteorites are produced by collisions（碰撞） between asteroids (small planets). These collisions probably happened many billions of years ago. This means the physical and chemical structure of a meteorite can give scientists information about the early days of the universe.
【小题1】          The story is about ___.     

A．floods caused by meteors

B．matter from outer space

C．life on Earth millions of years ago

D．meteorites that have damaged the moon

【小题2】          The Earth has ___.                    

A．three billion craters

B．fewer craters than the moon

C．more craters than the moon

D．a thinner atmosphere than the moon

【小题3】          Some scientists believe the dinosaurs became extinct because ___.     

A．they were hit by meteors

B．meteorites landed on their nests

C．meteorites landed and changed the climate

D．they could no longer breathe the atmosphere

【小题4】          Meteors are ___.                                         

A．small planets

B．the same as asteroids

C．from broken parts of asteroids

D．the light we see when meteoroids hit our atmosphere

Answer 1

【小题1】          B
【小题2】          B
【小题3】          C
【小题4】          D

解析试题分析：
【小题1】          本题为主旨大意题。本文在第一段提到了These moving lights are not, in fact, stars at all. They are small pieces of matter from outer space, which burn up as they enter the Earth’s atmosphere.点出了文章要论述的来自外太空的物质。接下来的两段分别阐述了流星体是如何产生的以及它们对于环境所造成的影响。由此我们知道，本篇文章是关于来自外太空的物质。故选B。
【小题2】          本题为细节题。由第二段的The moon, however, has about three billion craters陨石坑caused by meteorites impacting影响 its surface. The reason more meteorites have reached the surface of the moon than the surface of the Earth is that the moon does not have enough atmosphere for the meteorites to burn up in.可知地球上的陨石坑没有月球上的多。故选B。
【小题3】          本题为细节题。由第二段的最后一句话Some scientists believe it was a change of climate caused by meteorites hitting the Earth that resulted in the extinction of the dinosaurs and other large prehistoric animals.可知科学家们认为陨石撞击地球导致了恐龙和其他的史前动物的灭绝。故选C。
【小题4】          本题为概念题。由第一段的最后一句A meteor is actually the name given to the light we see when a meteoroid is burning up.可知D是正确答案。
考点：本篇为说明性的文章。
点评：文章以我们平常所见的“流星雨”开始，然后在第一段再向大家说明它们其实根本不是星星，而是流星体划过大气层时燃烧所发出的光。在接下来的两段中分别阐述了流星体是如何产生的以及它们对于环境所造成的影响。说明文往往在文章的首段就会点明主题，其他的问题可以在文章的阐述中找到答案。