If the population of the earth goes on increasing at its present rate, there will eventually not be enough resources left to sustain life on the planet.By the middle of the 21st century,if present trends continue, we will have used up all the oil that dri

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If the population of the earth goes on increasing at its present rate, there will eventually not be enough resources left to sustain life on the planet.By the middle of the 21st century,if present trends continue, we will have used up all the oil that drives our cars,for example.Even if scientists develop new ways of feeding the human race,the crowded conditions on earth will make it necessary for lus to look for open space somewhere else. But none of the other planets in our solar system are capable of supporting life at present. One possible solution to the problem, however,has recently been suggested by American scientist, Professor Carl Sagan.
Sagan believes that before the earth's resources are compleetely exhausted it will be possible to change the atmophere of Venus and so create a new world almost as large as earth itself. The difficult is that Venus is much hotter than the earth and there is only a tiny amount of water there.
Sagan proposes that algae organisms that can live in extremely hot or cold atmospheres and at the same time produce oxygen,should be bred in condition similar to those on Venus.As soon as this has been done, the algae will be placed in small rockets. Spaceship will then fly to Venus and fire the rockets into the atmosphere .In a fairly short time, the alge will break down the carbon dioxide into oxygen and carbon.
When the algae have done theri work, the atmosphere will become cooler,but befor man can set foot on Venus it will be neccessary for the oxygen to produce rain. The surface of the planet will still be too hot for man to land on it but the rain will eventually fall and in a few years something like earth will be reproduced on Venus.
On Venus there is a lot of ________.

a.water
b.carbon dioxide
c.carbon monoxide
d.oxygen

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相似问题和答案

第1题：

Continuity of life refers to whether an entity continues to operate or technically dissolves and ceases to exist in its present form. when a change occurs in the ownership structure.()

此题为判断题(对，错)。

答案：正确

第2题：

These natural resources will be______sooner or later if the present rate of exploitation continues.

A．depleted

B．deployed

C．inclined

D．mingled

正确答案：A
空格所在部分意思为：这些自然资源迟早都要被______。将各选项代入，只有depleted“使减少；弄空；耗尽……的资源”符合题意，因此本题选A。

第3题：

完形填空Many of the world’s pollution problems have been caused by the crowding of large groups of people into cities.Satisfying the 21 of the people leads to further polluting by industry.If the rapid increase in human population 22 at the present rate (比率), there may be much greater harm.Some scientists speak of the 23 in number of people as “Population Pollution”.

About 2000 years ago, the world 24 was probably about 250 million.It reached a billion in 1850.By 1930 the population was two billion.It is 25 three and a half billion.It is expected to double by the year 2000.If the population continues to grow at the same 26 , there would be 25 billion people in the world a hundred years from now.

Man has been using the earth’s 27 more and more rapidly over the years.Some of them are almost gone.Now many people believe that man’s greatest 28 is how to control the growth of this population.The materials in the world will not support the human population in time to come if the present rate of increase continues.29 there is over crowding in the cities and hunger in some countries.Can man’s rate of increase continue?

Many people believe that human survival (幸存者) in the future 30 on the answer to the question.

21.A.needs

B.supplies

C.service

D.supports

22.A.stops

B.continues

C.slows down

D.adds to

23.A.increase

B.reduce

C.country

D.improvement

24.A.people

B.situation

C.population

D.land

25.A.now

B.in the past

C.in the future

D.then

26.A.place

B.time

C.rate

D.result

27.A coal

B.oil

C.mines

D.resources

28.A.problem

B.power

C.plan

D.idea

29.A.Already

B.Yet

C.Still

D.Often

30.A.feeds

B.lives

C.keeps

D.depends

参考答案：BACAC DAAD

第4题：

Passage 2
If the population of the earth goes on increasing at its present rate, there will eventually not be enough resources left to sustain life on the planet. By the middle of the 21st century, if present trends continue, we will have used up all the oil that drives our cars, for example. Even if scientists develop new ways of feeding the human race, the crowded conditions on earth will make it necessary for us to look for open space somewhere else. But none of the other planets in our solar system are capable of supporting life at present. One possible solution to the problem, however, has recently been suggested by an American scientist, Professor Carl Sagan.
Sagan believes that before the earth's resources are completely exhausted it will be possible to change the atmosphere of Venus and so create a new world almost as large as earth itself. The difficulty is that Venus is much hotter than the earth and there is only a tiny amount of water there.
Sagan proposes that algae organisms, which can live in extremely hot or cold atmospheres and at the same time produce oxygen, should be bred in conditions similar to those on Venus. As soon as this has been done, the algae will be placed in small rockets. Spaceships will then fly to Venus and fire the rockets into the atmosphere. In a fairly short time, the algae will break down the carbon dioxide into oxygen and carbon.
When the algae have done their work, the atmosphere will become cooler, but before man can set foot on Venus it will be necessary for the oxygen to produce rain. The surface of the planet will still be too hot for men to land on it but the rain will eventually fall and in a few years something like earth will be reproduced on Venus.
CarlSagan believes that Venus might be colonized from earth because__________.

A. it might be possible to change its atmosphere
B. its atmosphere is the same as the earth's
C. there is a good supply of water on Venus
D. the days on Venus are long enough

答案：A

解析：

由第二段第一句中的“itwill be possible to change the atmosphere ofVenus and so create a new worl d”可知.so是表示因果的连接词，前因后果，所以正确答案A。

第5题：

A. water
B. carbon dioxide
C. carbon monoxide
D. oxygen

答案：B

解析：

由第--f&的最后一句话中的“there is only a tiny amount ofwater there(Venus)”得知，A选项错误。第三段结尾说明，藻类通过火箭运往金星，然后“In a fairly short time，the algae will break down the carbon dioxide into oxygen and carbon”.说明金星上有大量的二氧化碳。C和D选项错误。故选B。

第6题：

Which of the following statements is NOT true?

A) World population is increasing at a rate of 150 per minute.

B) Lower death rates also contribute to world population growth.

C) The population of Columbia has been doubling every year for 21 years.

D) The United States is usually doubling its population about every 87 years.

正确答案：C
答案：C
[试题分析] 事实判断题。
[详细解答] 根据第三段第一句World population is increasing at a rate of 9,000 per hour．可判断A世界人口每分钟增加150人正确；根据该段第二句This is not only due to higher birth rates，but to lower death rates as well．可判断B论断正确；而由第四段的Some countries，such as Columbia， Thailand，Morocco，Costa Rica，and the Philippines．are doubling their populations about every twenty-one years可判断， C哥伦比亚人口持续21年每年翻一番的论断混淆了事实，论断错误；D美国人口每87年翻一番可根据第三段第二句The United States is doubling its population about every eighty-seven years一句判断为正确论断。因此，本题答案为C。

第7题：

By the middle of the 21st century，the vast majority of the world‘s population will be living in cities _______ in the country. A. other than B. more than C. better than D. rather than

正确答案：D
rather than：与其…（不如）；不是…（而是）。句意：到二十一世纪中叶，世界上大多数人口将生活在城市而不是农村。（本解析由学员提供）

第8题：

Population experts tell us that by the year 2025, the population in cities in developing nations will increase to five times its present size.()

参考答案：错误

第9题：

Passage 2
If the population of the earth goes on increasing at its present rate, there will eventually not be enough resources left to sustain life on the planet. By the middle of the 21st century, if present trends continue, we will have used up all the oil that drives our cars, for example. Even if scientists develop new ways of feeding the human race, the crowded conditions on earth will make it necessary for us to look for open space somewhere else. But none of the other planets in our solar system are capable of supporting life at present. One possible solution to the problem, however, has recently been suggested by an American scientist, Professor Carl Sagan.
Sagan believes that before the earth's resources are completely exhausted it will be possible to change the atmosphere of Venus and so create a new world almost as large as earth itself. The difficulty is that Venus is much hotter than the earth and there is only a tiny amount of water there.
Sagan proposes that algae organisms, which can live in extremely hot or cold atmospheres and at the same time produce oxygen, should be bred in conditions similar to those on Venus. As soon as this has been done, the algae will be placed in small rockets. Spaceships will then fly to Venus and fire the rockets into the atmosphere. In a fairly short time, the algae will break down the carbon dioxide into oxygen and carbon.
When the algae have done their work, the atmosphere will become cooler, but before man can set foot on Venus it will be necessary for the oxygen to produce rain. The surface of the planet will still be too hot for men to land on it but the rain will eventually fall and in a few years something like earth will be reproduced on Venus.
Man can eventually land on Venus only when__________.

A. the algae have done their work
B. the atmosphere becomes cooler
C. there is oxygen
D. it rains there

答案：D

解析：

由最后一段中“before man can set foot on Venus it will be necessary for the oxygen to produce rain”可知，只有金星上有降雨，人类才最终有可能在上面着陆。所以正确答案为D。

第10题：

Passage 2
If the population of the earth goes on increasing at its present rate, there will eventually not be enough resources left to sustain life on the planet. By the middle of the 21st century, if present trends continue, we will have used up all the oil that drives our cars, for example. Even if scientists develop new ways of feeding the human race, the crowded conditions on earth will make it necessary for us to look for open space somewhere else. But none of the other planets in our solar system are capable of supporting life at present. One possible solution to the problem, however, has recently been suggested by an American scientist, Professor Carl Sagan.
Sagan believes that before the earth's resources are completely exhausted it will be possible to change the atmosphere of Venus and so create a new world almost as large as earth itself. The difficulty is that Venus is much hotter than the earth and there is only a tiny amount of water there.
Sagan proposes that algae organisms, which can live in extremely hot or cold atmospheres and at the same time produce oxygen, should be bred in conditions similar to those on Venus. As soon as this has been done, the algae will be placed in small rockets. Spaceships will then fly to Venus and fire the rockets into the atmosphere. In a fairly short time, the algae will break down the carbon dioxide into oxygen and carbon.
When the algae have done their work, the atmosphere will become cooler, but before man can set foot on Venus it will be necessary for the oxygen to produce rain. The surface of the planet will still be too hot for men to land on it but the rain will eventually fall and in a few years something like earth will be reproduced on Venus.

In the long run, the most difficult problem caused by population growth on earth will probably be the lack of__________.
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A．food
B．oil
C．space
D．resources

答案：C

解析：

由第一段可知，如果人口按照目前速度持续膨胀的话，地球上最终会缺乏资源来维持这么多的生命。即使科学家发明出替代资源，拥挤的人口也使我们不得不到其他星球寻找生存空间。但是目前太阳系还没有发现能维持生命的行星。因此和缺乏资源相比，缺乏生存空间才是最令人担忧、最难解决的问题。所以正确答案为C。

If the population of the earth goes on increasing at its present rate, there will eventually not be enough resources left to sustain life on the planet.By the middle of the 21st century,if present tr

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