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（滅絕）. 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隕石坑caused by meteorites impacting影響 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.

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

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

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

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

【答案】

1.B

2.B

3.C

4.D

【解析】文章介紹了來自外太空的隕石撞擊地球可能會導致地球環境的巨大變化，導致物種滅絕。

1.B 主旨大意題 文章講述的是來自外太空的物質——隕石。故B正確。

2.B 細節題 根據第三段五，六行. 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.可知地球的隕石坑比月球要少。

3.C 推理題、根據文章第三段第五行開始的內容可知人們認為恐龍的滅絕是因為隕石撞擊地球，導致地球的環境發生巨大變化，最后恐龍滅絕了。

4.D 細節題。根據文章第一段最后一句. A meteor is actually the name given to the light we see when a meteoroid is burning up.可知D正確。