Sulphur has occasionally been found in the earth in an almost pure state.A:regularly B:accidentally C:sometimes D:successfully

However,it has been found that even people insensitive to a certain smell at first can suddenly become sensitive to it when（ ）to it often enough.

A.subjected
B.left
C.drawn
D.exposed

共用题干
To Survive or to Vanish

1.Over 3.6 billion years ago,the first creature was born in the world.Since then,the earth started its era with life.The history of life on earth has been a history of interaction between living things and their surroundings.To a large extent,the physical form and the habits of the earth's vegetation and its animal life have been molded by the environment. Considering the whole span of earthly time,the opposite effect,in which life actually modifies its surroundings,has been relatively slight. Only in the present century has one species一man acquired significant power to alter the nature of his world.
2.During the past 25 years,this power has not only become increasingly great but it has changed in character. The most alarming of all man's assaults upon the environment is the contamination of air,earth,rivers,and sea with dangerous and even lethal materials. This pollution is for the most part irrecoverable.In this now universal contamination of the environment,chemicals are the sinister partners of radiation in changing the very nature of the world the very nature of its life. Chemicals sprayed on croplands or forests or gardens lie long in soil,entering into living organisms, passing from one to another in a chain of poisoning and death.Or they pass mysteriously by underground streams until they emerge and combine into new forms that kill vegetation,sicken cattle,and work unknown harm on those who drink from once pure wells."Man can hardly even recognize the devils of his own creation,"as a scientist has said.
3.Hundreds of millions of years have passed before the globe produced the life that now inhabits the earth.Given time not in years but in millennia life adjusts,and a balance has been reached.But in the modern world there is no time.
4.The quick steps of change follows the impetuous pace of man rather than the deliberate pace of nature.Radiation is now the unnatural creation of man's tampering with the atom.The chemicals are the synthetic creations of man's inventive mind,having no counterparts in nature.
5.To survive these chemicals would require not merely the years of one man's life but the life of generations.And even this,were it by some miracle possible,would be futile,for the new chemicals come from our laboratories in an endless stream;almost five hundred annually find their way into actual use in the United States alone.Among them are many that are used in man's war against nature.Since the mid l940's over 200 basic chemicals have been created for use in killing insects,weeds,and other organisms described as"pests".
6.It is not my contention that chemical insecticides must never he used.I do contend that we have put poisonous and biologically potent chemicals indiscriminately into the hands of persons largely or wholly ignorant of their potentials for harm. We have subjected enormous numbers of people to contact with these poisons,without their consent and often without their knowledge.I contend,furthermore,that we have allowed these chemicals to be used with little or no advance investigation of their effect on soil,water,wildlife,and man himself. Future generations are unlikely to forgive our lack of concern for the integrity of the natural world that supports all life.

The effect of life modifying its surroundings has been_______.
A:man's tampering with the atom
B:enormous numbers of people to contact with these poisons
C:the integrity of the natural world that supports all life
D:inventive
E:irrecoverable
F:relatively slight

It may be pointed out that warfare（战争）as practiced by man has no parallel in nature,This is to say that within the more highly developed animal populations of this earth,there is not now.nor has there been similar destruction within a species（物种）itself.In fact,one has to go to the lowliest forms of animal life,such as certain kinds of ants,to find anything comparable to human warfare.It is a curious fact that mankind appears to give the killing of his own kind a good reason by imaging that it is a"law of nature".There are now a lot of wrong ideas about the laws of nature,of which this is one of the most incorrect and fateful（致命的）.Political beliefs have been based upon it with results that have come near to destroying human civilization.The theory that war is a biological necessity.that it is nature′s method of controlling population and believing in the survival（生存）of the strong and the elimination（灭亡）of the weak,is totally wrong and insupportable.Within the last century.when wars have been common all over the world,the human population of the earth has almost doubled.

The author of this passage seems to be the"law of nature".

A.against
B.in favor of
C.uncertain of
D.very much interested in

It may be pointed out that warfare（战争）as practiced by man has no parallel in nature,This is to say that within the more highly developed animal populations of this earth,there is not now.nor has there been similar destruction within a species（物种）itself.In fact,one has to go to the lowliest forms of animal life,such as certain kinds of ants,to find anything comparable to human warfare.It is a curious fact that mankind appears to give the killing of his own kind a good reason by imaging that it is a"law of nature".There are now a lot of wrong ideas about the laws of nature,of which this is one of the most incorrect and fateful（致命的）.Political beliefs have been based upon it with results that have come near to destroying human civilization.The theory that war is a biological necessity.that it is nature′s method of controlling population and believing in the survival（生存）of the strong and the elimination（灭亡）of the weak,is totally wrong and insupportable.Within the last century.when wars have been common all over the world,the human population of the earth has almost doubled.

According to Sentence 2,which of the following is true?

A.The destruction is similar to the killing of each other within human beings.
B.There is not the similar destruction now,but it occurred before.,'
C.There is never a time when we may see the similar destruction.
D.The destruction is now a thing of the past.

共用题干
Where Has the Salt Come from?

Every now and then,we meet a fact about our earth that makes us feel strange and no
answer for the fact has yet been found.Such a fact is the existence of salt in the oceans.
How did it get there?
We simply do not know how the salt got into the ocean!We do know,of course,that
salt is water-soluble,and so passes into the oceans with rainwater.The salt of the earth's
surface is constantly being dissolved（溶解）and is passing into the ocean.
But we do not know whether this can explain the huge quantity of salt in oceans.If all
the oceans were dried up,enough salt would be left to build a wall 180 miles high and a
mile thick. Such a wall would reach once around the world at the Equator（赤道）!
The common salt that we all use is produced from seawater or the water of salt lakes,
from salt springs（源泉）and from deposits of rock salt. The concentration（浓度）of salt in
seawater ranges from about three percent to three-and-one-half percent. The Dead Sea,
which covers an area of about 340 square miles,contains about 11,600,000,000 tons of
salt!
On the average, a gallon（加仑）of seawater contains about a quarter of a pound of
salt.The beds of rock salt that are found in various parts of the world were all originally
formed by the evaporation（蒸发）of seawater millions of years ago. It is believed that the
thick rock-salt deposits were formed after about nine-tenth of theY volume of seawater had
been evaporated.
Most commercial salt is obtained from rock salt.The usual method is to drill wells（井）
down to the salt beds. Pure water is pumped down（抽进去）through a pipe. The water
dissolves the salt and it is forced through another pipe up to the surface.

The author is sure that the dissolved salt from the earth's surface is the only source of the huge quantity of salt found in oceans.
A:Right
B:Wrong
C:Not mentioned

如果知道表示软件等“和……兼容”的短语“be compatible with”，就可以很容易地解答问题。

A.has found
B.has been found
C.finds
D.was finding

Your shipment of goods has been found short ( ) weight by CIQ.
A. out B. on
C. in D. with

It may be pointed out that warfare（战争）as practiced by man has no parallel in nature,This is to say that within the more highly developed animal populations of this earth,there is not now.nor has there been similar destruction within a species（物种）itself.In fact,one has to go to the lowliest forms of animal life,such as certain kinds of ants,to find anything comparable to human warfare.It is a curious fact that mankind appears to give the killing of his own kind a good reason by imaging that it is a"law of nature".There are now a lot of wrong ideas about the laws of nature,of which this is one of the most incorrect and fateful（致命的）.Political beliefs have been based upon it with results that have come near to destroying human civilization.The theory that war is a biological necessity.that it is nature′s method of controlling population and believing in the survival（生存）of the strong and the elimination（灭亡）of the weak,is totally wrong and insupportable.Within the last century.when wars have been common all over the world,the human population of the earth has almost doubled.

What does the"law of nature"mean?You can find the answer in the passage in

A.the first sentence
B.the fourth sentence
C.the seventh sentence
D.the final sentence