The year is 2094．It has been announced that a comet (彗星) is heading towards the Earth．Most of it will miss our planet , but two pieces will probably hit the southern half of the Earth．

On 17 July , a piece four kilometers wide enters the Earth’s atmosphere (大气层) with a massive explosion．About half of the piece is destroyed , but the remaining part hits the South Atlantic at 200 times the speed of sound．The sea boils and a huge hole is made in the sea bed．Huge waves are created and spread outwards from the hole．The wall of water , a kilometer high , rushes towards southern Africa at 800 kilometers an hour．Cities on the African coast are totally destroyed and millions of people re drowned．

Before the waves reach South America , the second piece of the comet lands in Argentina．Earthquakes and volcanoes are set off in the Andes Mountains．The shock waves move north into California and all around the Pacific Ocean．The cities of Los Angeles , San Francisco and Tokyo are completely destroyed by earthquakes．Millions of people in the southern half of the earth are already dead, but the north won’t escape for long．Because of the explosions , the sun is hidden by clouds of dust , temperatures around the world fall to almost zero．Crops are ruined．The sun won’t be seen again for many years．Wars break out as countries fight for food．A year later , no more than 10 million people remain alive．

Could it really happen ? In fact , it has already happened more than once in the history of the Earth．The dinosaurs were on the Earth for over 160 million years．Then 65 million years ago they suddenly disappeared．Many scientists believe that the Earth was hit by a piece of object in space．The dinosaurs couldn’t live through the cold climate that followed and they died out．Will we meet the same and ?

1.What is mainly described in the passage ?

         A．A historic discovery．        B．An event of imagination

         C．A research on space．      D．A scientific adventure．

2.When the first piece hits the South Atlantic , it causes          ．

         A．an earthquake                             B．damages to cities

         C．an Earth explosion   D．huge waves

3.Why can’t the northern half of the earth escape for long ?

         A．Because the land is covered with water

         B．Because the light and heat from the sun can not reach the earth．

         C．Because people there can not live at the temperature of zero．

         D．Because wars break out among countries．

4.By giving the example of dinosaurs , the author tries to prove        ．

         A．animals could not live in the cold climate

         B．what happened 65 million years ago was an invented story

         C．the human beings will die out in 2094

         D．the Earth could be hit by other objects in space

 

   Many scientists are now exploring the idea of going to live on Mars. Some other scientists from the MASA AMES Center(美国宇航局) have already started the creation of a “Mars town” and many others are in fact already experimenting with it. Of course, these experiments are done on Earth itself but this “Mars town” has an environment practically like that of Mars.

  The astronauts working in these towns wear their space suit and also do everything they would really have to carry out if they ever go to Mars in the future.

   But Mars would be like Earth, a temporary（临时的） place for humans. When the Sun starts swallowing up(吞掉) the planets, Mars will disappear only hours after Earth. So Mars only seems to be the ideal place to spread the human beings. It is also a good location to send humans if ever there is a disaster on Earth. By saying disaster, I mean asteroids(小行星) hitting and things like that.

   If we humans do not want to disappear when Earth or Mars gets swallowed up, we will have to go and live beyond the solar system. But are there any planets outside our solar system prepared to support life? Astronomers’ answer is:

   “If Earth can support life, why can’t other planets do the same too? Astronomers have already discovered a Jupiter(木星)- like planet orbiting a Sun-like star, so why not an Earth-like planet orbiting a Sun-like star?

   To achieve this goal though, many other problems have to be taken into consideration. How do we transform(改造) a dusty planet like Mars into one more or less like our Earth? How should we go on? There is still a long way to go.

The “Mars town” mentioned in the passage is ___________

   A. a research base on Mars.

   B. an experimental lab built on Earth.

   C. a strange place on Mars .

   D. a town existing in scientists’ imagination

We can know from the passage that astronomers probably think ____________

   A. it is impossible to transport humans to other planets.

   B. there may be an Earth-like planet outside the solar system

   C. humans will move to the new-found Jupiter-like planet

   D. there’s no need for humans to move beyond the solar system.

Why would Mars only be a temporary(临时) place for humans?

   A. The conditions there would be too hard for the human beings

   B. There would be more disasters like asteroids hitting.

   C .It would disappear when Earth disappeared.

   D. It would be too hot to live on.

The underlined word “orbiting” in the fifth paragraph is closest in meaning to “________”

   A. moving around           B. getting close to

   C. passing by quickly        D. going through

Which of the following would be the best title for this passage?

   A. Mars Town                           B. Living on Mars

   C. The Future of Earth                    D. Where to live in the Future

Some scientists say that animals in the oceans are increasingly threatened by noise pollution caused by human beings.

The noise that affects sea creatures comes from a number of human activities. It is caused mainly by industrial underwater explosions, ocean drilling, and ship engines. Such noises are added to natural sounds. These sounds include the breaking of ice fields, underwater earthquakes, and sounds made by animals themselves.

Decibels (分贝) measured in water are different from those measured on land. A noise of one hundred and twenty decibels on land causes pain to human ears. In water, a decibel level of one hundred and ninety－five would have the same effect.

Some scientists have suggested setting a noise limit of one hundred and twenty decibels in the oceans. They have observed that noises at that level can frighten and confuse whales（鲸鱼）.

A team of American and Canadian scientists discovered that louder noises can seriously injure some animals.

The research team found that powerful underwater explosions were causing whales in the area to lose their hearing. This seriously affected the whales' ability to exchange information and find their way. Some of the whales even died. The explosions had caused their ears to bleed and become infected(被感染的).

Many researchers whose work depends on ocean sounds are against a limit of one hundred and twenty decibels. They say such a limit would mean an end to important industrial and scientific research.

Scientists do not know how much and what kinds of noises are harmful to ocean animals. However, many scientists don’t think that noise is a greater danger than they believed. They want to prevent noises from harming creatures in the ocean.

1.According to the passage, which of the following is increasingly dangerous to sea creatures?

A. The sound of cars.

B. The sound of voices.

C. Man-made noise pollution.

D. The sound of steps.

2.According to the passage, natural sounds include all of the following EXCEPT________.

A. sounds made by animals themselves                        B. ocean drilling

C. underwater earthquakes                                            D. the breaking of ice fields

3.Which of the following is discussed in the third paragraph?

A. The same noise level produces a different effect on land and in the ocean.

B. Different places may have different types of noises.

C. The decibel is not a right unit (单位) for measuring underwater noise.

D. Different ocean animals may have different reactions to noises.

4. Which of the following is true of whales?      

A. They won't be confused by noises.

B. They are deaf to noises.

C. Their ability to reproduce will be lowered by high-level noises.

D. Their hearing will be damaged by high-level noises.

5.According to the passage, what will scientists most probably do in the future?

A. They will work hard to reduce ocean noise pollution.

B. They will protect animals from harmful noises.

C. They will try to set a limit of 120 decibels.

D. They will study the effect of ocean noise pollution.

 

．The fact has worried many scientists ______ the earth is becoming warmer and warmer these years.

A．what

B．which

C．that

D．though

 

The fact has worried many scientists ______ the earth is becoming warmer and warmer these years.

A. what          B. which         C. that       D. though