Our earth has been threatened by all kinds of pollutions.Acid rain is a kind of air pollut

______the atmosphere around our Earth, we would not be able to live.

A．Had it not been for

B．Would it not be for

C．If it has not been for

D．If it were not for

comet (慧星). When the fragments (碎片) landed in the southern part of the giant planet, the explosions were watched by scientists here on earth. But what if our own planet was hit by a comet？

The year is 2094. It has been announced that a comet is heading towards the Earth. Most of it will miss our planet, but two fragments will probably hit the southern part of the Earth. The news has caused panic.

On 17 July, a fragment four kilometers wide enters the Earth' s atmosphere with a huge explosion. About half of the fragment is destroyed. But the major part survives and hits the South Atlantic at 200 times the speed of sound. The sea boils and an enormous wave is created and spreads. The wall of water rashes towards southern Africa at 800 kilometres an hour. Cities On the African coast are totally destroyed and millions of people are drowned. The wave moves into the Indian Ocean and heads towards Asia.

Millions of people are already dead in the southern part of the Earth, but the north won't escape for long. Tons of broken pieces are thrown into the atmosphere by the explosions. As the sun is hidden by clouds of dust, temperatures around the world fall to almost zero. Crops are mined. Wars break out as countries fight for food. A year later civilization has collapsed. No more than 10 million people have survived.

Could it really happen？ In fact, it has already happened more than once in the history of the Earth. The dinosaurs(恐龙)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 space fragment. The dinosaurs couldn't survive in the cold climate that followed and they became extinct. Will we meet the same end？

Which of the following is NOT TRUE according to the author's description of the disaster in 2094？

A．The whole world becomes extremely cold.

B．All the coastal cities in Africa are destroyed.

C．The whole mankind becomes extinct.

D．The visit of the comet results in wars.

B

In July 1994 Jupiter, the largest planet in our solar system, was struck by 21 pieces of a comet (彗星). When the fragments (碎片) landed in the southern part of the giant planet, the explosions were watched by scientists here on earth. But what if our own planet was hit by a comet？

The year is 2094. It has been announced that a comet is heading towards the Earth. Most of it will miss our planet, but two fragments will probably hit the southern part of the Earth. The news has caused panic.

On 17 July , a fragment four kilometers wide enters the Earth ' s atmosphere with a huge explosion. About half of the fragment is destroyed. But the major part survives and hits the South Atlantic at 200 times the speed of sound. The sea boils and an enormous wave is created and spreads.

The wall of water rushes towards southern Africa at 800 kilometres an hour. Cities on the African coast are totally destroyed and millions of people are drowned. The wave moves into the Indian Ocean and heads towards Asia.

Millions of people are already dead in the southern part of the Earth, but the north won' t escape for long. Tons of broken pieces are thrown into the atmosphere by the explosions. As the sun is hidden by clouds of dust, temperatures around the world fall to almost zero. Crops are ruined. Wars break out as countries fight for food. A year later civilization has collapsed. No more than 10 million people have survived.

Could it really happen？ In fact, it has akeady happened more than once in the history of the Earth. The dinosaurs(恐龙)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 space fragment.

The dinosaurs couldn ' t survive in the cold climate that followed and they became extinct. Will we eet the same end？

61. Which of the following is NOT TRUE according to the author ' s description of the disaster in 2094？

[ A] The whole world becomes extremely cold.

[ B ] All the coastal cities in Africa are destroyed.

[ C] The whole mankind becomes extinct.

[ D] The visit of the comet results in wars.

, since nearly 75% of the earth's surface is covered with water. But about 97% of this huge amount is seawater,__ 1_ salt water. Man can only drink and use the other 3% of the fresh water that comes from rivers, lakes, underground, and other _2__.

And we can't even use all of that, because some of it is in the form. of icebergs and glaciers. Even worse, some of it has been polluted.

However, as things stand today, this small amount of fresh water, which is constantly being replaced by rainfall, is still enough for us. But our need_ 3__ water is increasing rapidly – almost day by day. We all have to learn how to stop wasting our previous water. One of the first steps we should _4_ is to develop ways of reusing it.

Experiments have already been done in this__ 5_ but only on a small scale. The systems that have been worked out resemble those used in spacecraft.

A、take

B、or

C、sources

D、for

E、case

48 查看材料

A.Tegmark fears he may hold the record for the longest time taken to read one book.

B.In a more positive vein， this is a wonderful collection of essays to dip in and out of if you already have a good overview （概述） of current cosmic understanding.

C.Levy is an active astronomer and an accomplished writer， so you"d expect him to provide a broad and accurate picture of our current understanding of the cosmos.

D.Scientific American has attempted to cater to this need by bringing together essays that have appeared in the magazine.

E.To some extent， these could have been plugged with a glossary （词表）. of terms.

F.Also included are contributions on the world of subatomic particles， the origin of life on the Earth and the possibility of its existence elsewhere.

47 查看材料

A.Tegmark fears he may hold the record for the longest time taken to read one book.

B.In a more positive vein， this is a wonderful collection of essays to dip in and out of if you already have a good overview （概述） of current cosmic understanding.

C.Levy is an active astronomer and an accomplished writer， so you"d expect him to provide a broad and accurate picture of our current understanding of the cosmos.

D.Scientific American has attempted to cater to this need by bringing together essays that have appeared in the magazine.

E.To some extent， these could have been plugged with a glossary （词表）. of terms.

F.Also included are contributions on the world of subatomic particles， the origin of life on the Earth and the possibility of its existence elsewhere.

49 查看材料

A.Tegmark fears he may hold the record for the longest time taken to read one book.

B.In a more positive vein， this is a wonderful collection of essays to dip in and out of if you already have a good overview （概述） of current cosmic understanding.

C.Levy is an active astronomer and an accomplished writer， so you"d expect him to provide a broad and accurate picture of our current understanding of the cosmos.

D.Scientific American has attempted to cater to this need by bringing together essays that have appeared in the magazine.

E.To some extent， these could have been plugged with a glossary （词表）. of terms.

F.Also included are contributions on the world of subatomic particles， the origin of life on the Earth and the possibility of its existence elsewhere.

. They are, 【C1】______ , energy efficiency, re-cycling, water 【C2】______ , alternative transportation, pollutant information and outdoor 【C3】______ . Each one, as you can see, is wholly concerned with human problems, human systems, human safety and 【C4】______ how (American) humans can go on living 【C5】______ the same material level over the long haul 【C6】______ messing things up for them-selves. 【C7】______ on that list is there any consideration of what are thought to be animals (or trees or rivers) rights; nowhere any regard for the ongoing 【C8】______ of species caused by humans; nowhere a 【C9】______ for the countless other species that are being 【C10】______ daily by the destruction and poisoning of habitats; nowhere any thought given to the 【C11】______ of the natural systems of the living earth and learning to live in them as the first people did. 【C12】______ all, nowhere on the list is there found any consideration of wilderness, of the need for a healthy earth to have places where humans don't 【C13】______ , where the full complexity and diversity of life are allowed to 【C14】______ unaffectedly. All that the Earth Day people can see is something called "just think of the 【C15】______ " of "outdoors", and all they can think of doing there is human "recreation".

The reason that is important is that 【C16】______ the human understands itself as a species "reapplies for membership in the biosphere", as the eco-historian Thomas Berry has 【C17】______ it, "it will never stop treating the earth and its treasures (resources) as the rightful food for its omnivorous maw (杂食性动物的胃), will never stop acting as if it owns the earth and has the right of control 【C18】______ its species". This is a matter of passing laws or double-panning windows; this is a deep reordering of values, a new (and very' old) way of understanding the earth and its species as sacred, an ecological 【C19】______ that go right to the heart of our lives. Without it no 【C20】______ changes will come, or last.

【C1】

A．of course

B．on condition

C．in practice

D．with regards

blue dot hidden in the blazing light of our sun. While our neighbors Venus and Mars would reflect a fairly even glow, Earth would put on a little show. Earth's light would brighten and dim as it spins, because oceans, deserts, forests and clouds—which are all too small to be seen from such a distance-reflect varying amounts of sunlight. The variations, it turns out, are so strong and distinctive that surprising amount of information could be taken from a simple ebb and flow of light. Scientists at Princeton University and the Institute for Advanced Study conducted a detailed study of Earth's reflections as a way for human scientists to learn about distant planets that may be like our own.

(2) "If you looked at our solar system from far away, and you looked at the terrestrial planets--Mercury, Venus, Earth and Mars--one of the quickest ways to see that Earth is unique is by looking at the light curve," said Ed Turner, professor of astrophysics and a co-author of the study. "Earth has by far the most complicated light curve." The standard thinking in the field had been that most of the information about an Earth-like planet would come from spectral analysis, a static reading of the relative component of different colors within the light, rather than a reading of changes over time. Spectral analysis would reveal the presence of gases such as water vapor, carbon dioxide and oxygen, in the planet's atmosphere, looking at the change in light over time docs not replace spectral analysis, but it could greatly increase the amount of information scientists could learn, said Turner. It may indicate, for example, the presence of weather, oceans, ice or even plant life.

"Earth would put on a little show" means: as it spins, ______.

A．Earth is a more active planet than Venus and Mars

B．Earth reflects a brighter light curve than Venus and Mars

C．Earth shows oceans, deserts, forests and clouds, while Venus and Mars don't

D．Earth reflects sunlight in an ebb-and-flow manner