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Passage Two Modern humans emerged some 250,000 years ago, yet agriculture is a fairly

recent invention, only about 10,000 years old. Many crop plants are rather new additions to our diet: broccoli (a flowering mutant of kale) is thought to be only 500 years old. Most innovation is far more recent still. Although Austrian monk Gregor Mendel's pea plant experiments quietly laid the basic foundations of genetics in the mid-19th century, his work was rediscovered and applied to crop breeding only at the beginning of the 20th century. Further advances have steadily accumulated. The 1940s saw the identification of DNA as genetic material and the adoption, by commercial breeders, of genetic modification - typically by applying chemicals or radiation to DNA to try to make plants with advantageous characteristics. The modifications ultimately led to the green revolution of the 1960s and 1970s, during which time global wheat yields tripled. The 1980s and 1990s saw the commercial adoption of agricultural biotechnology, which has allowed breeders to introduce specific genes into crops from the same or different species. In 2004 the first plant genome was fully sequenced, and since then the number of plant gene sequences in GenBank, the public repository for gene sequence information, has been doubling every two years. Our knowledge is increasing exponentially, as it has been in other fields such as semiconductors and cellular telephony. Our challenge is to increase agricultural yields while decreasing the use of fertilizer, water, fossil fuels and other negative environmental inputs. Embracing human ingenuity and innovation seems the most likely path. Plants did not evolve to serve humans, and their sets of genes are incomplete for our purposes. The integral role of modifying genes is obvious to all breeders, though sometimes painfully absent from the public's understanding of how modern agriculture succeeds. All breeding techniques, from before Mendel's time until today, exploit modifications to plant DNA. These modifications can take the form. of mistakes or mutations that occur during natural cell division in the wild; the natural but random movement of DNA sequences from one part of a plant's genome to another; or the more precise insertion of known gene sequences using biotechnology. In all these cases, plant genes are moved within or across species, creating novel combinations. Hybrid genetics - the combination of different versions of the same gene – has resulted in spectacular yield increases. Largely as the consequence of using hybrid seed varieties, corn yields in the U.S. have increased more than 500 percent in the past 70 years. Questions 6-10 are based on Passage Two.

(1)Which statement is correct according to paragraph one？

A、Broccoli was first bred by Mendel

B、Broccoli wasn’t considered edible until 500 years ago

C、Mendel's work was considered most important in the history of genetics

D、Mendel’s study found its major application some 100 years ago

(2)What was cited as a result of the green revolution？

A、Sharp rise in worldwide wheat production

B、Extensive use of organic fertilizer

C、Large-scale adoption of genetic modification

D、Commercial success of genetically modified seeds.

(3)Which statement is true of GenBank according to the passage？

A、The number of gene sequences has doubled since its foundation

B、The commercial breeders are its main sponsors

C、It is a genetic sequence database

D、It was founded in 2004

(4)It can be learned from the passage that the significance of genetic modification is ______.

A、questioned by some critics

B、poorly conveyed to the public

C、appreciated by all breeders

D、fully understood only by scientists

(5)The word “novel” in paragraph three is closest in meaning to ______.

A、artificial

B、various

C、hybrid

D、new

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更多“Passage Two Modern humans emer…”相关的问题

第1题

Passage One Valencia is in the east part of Spain. It has a port on the sea, two miles a

Passage One

Valencia is in the east part of Spain. It has a port on the sea, two miles away from the coast. It is the capital of a province that is also named Valencia.

The city is the market centre for what is produced by the land around the city. Most of the city's money is made from farming. It is also a busy business city with ships, railways, clothes and machine factories.

Valencia has an old part with white buildings, coloured roofs, and narrow streets. The modern part has long, wide streets and new buildings. Valencia is well known for its parks and gardens. It has many old churches and museums. The University in the centre of the city was built in the 13(上标)th century.

The city of valencia has been known since the 2(上标)nd century. In the 8(上标)th century it was the capital of Spain. There is also an important city in Venzuela(委内瑞拉)named Valencia.

36. The main income of the city of Valencia is from its______.

A. markets

B. business

C. factories

D. farming

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第2题

According to the passage，a great variety of influenza strains can appear when______. A. H

According to the passage，a great variety of influenza strains can appear when______.

A. H and N spikes are produced

B. animal and bird viruses are combined

C. dissimilar types virus recombine

D. two viruses of the same type are contracted

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第3题

Passage Two Started in 1636, Harvard University is the oldest of all the many coll

Passage Two

Started in 1636, Harvard University is the oldest of all the many colleges and universities in the United States. Yale, Princeton, Columbia and Dartmouth were opened soon after Harvard.

In the early years, these schools were much alike. Only young men went to college. All the students studied the same subjects, and everyone learned Latin, Greek and Hebrew. Little was known about science then, and one kind of school could teach everything that was known about the world. When the students graduated, most of them became ministers (大臣) or teachers.

In 1782, Harvard started a medical school for young men who wanted to become doctors. Later, lawyers could receive their training in Harvard's law school. In 1825, besides Latin and Greek, Harvard began teaching modern languages, such as French and German. Soon it began teaching American history.

As knowledge increased, Harvard and other colleges began to teach many new subjects. Students were allowed to choose the subjects that interested them.

Today, there are many different kinds of colleges and universities. Most of them are made up of smaller schools that deal with (涉及) special fields of learning. There's so much to learn that one kind of school can't offer it all.

36. The oldest university in the US is______.

A. Yale

B. Princeton

C. Harvard

D. Columbia

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第4题

In 1798 the political economist Malthus predicted that in time mankind would face starvati
on, having outgrown the available food supplies. Today, a century and a half later, there are still experts who forecast the same global disaster—unless urgent measures are taken to prevent it. By the end of the present century there may well be over five thousand million people living on this globe, an increase of over fifty percent on todays figure. In order to keep pace with this increase in mankind the farmers of the world will have to step up their production of food by at least two percent every year. Such a rate of increase has never been maintained in any country by conventional methods of agriculture, despite modern mechanization and the widespread use of fertilizers. There are no large worthwhile reserves of potential farmland remaining, and good fertile land is continually being changed into industrial use. Moreover, erosion of the soil takes a constant toll (损失). Intensive research, carried out over many years in all manners of climate conditions, has produced a revolutionary method of growing crops without using any soil at all. Hydroponics (水栽 法), as this technique is called, may well be the answer to all our food worries; already it has accomplished wonders in producing huge crops. Hydroponics was once a complicated and expensive business, now it is well out of the experimental stage. Labor costs are far lower than when normal methods of agriculture are employed. In fact, it is a completely automatic system. There is no hard manual work, no digging or ploughing, and no weeding to speak of. Yields can be far higher than they are in soil.

Which of the following best sums up the whole passage？

A．Malthus" prediction has been proved to be correct by modern experts.

B．Hydroponics is a new development in agriculture.

C．Hydroponics may be the answer to the world food shortage in the future.

D．Conventional methods of agriculture should be improved so as to step up food production by two percent every year.

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第5题

Questions 61-65 are based on Passage Two:Passage TwoScience is a dominant theme in our cul

Questions 61-65 are based on Passage Two:

Passage Two

Science is a dominant theme in our culture．Since it touches almost every facet of our life, educated people need at least some acquaintance with its structure and operatiom They should also have an understanding of the subculture in which scientists live and the kinds of people they are, An understanding of general characteristics of science as well as specific scientific concepts is easier to attain if one knows something about the things that excite and frustrate the scientist．

This book is written for the intelligent student or lay person whose acquaintance with science is superficial; for the person who has been presented with science as a musty storehouse of dried facts; for the person who sees the chief objective of science as the production of gadgets; and for the person who views the scientist as some sort of magician． The book can be used to supplement a course in any science, to accompany any course that attempts to give an understanding of the modern world, or-independent of any course-simply to provide a better understanding of science．We hope this book will lead readers to a broader perspective on scientific attitudes and a more realistic view of what science is, who scientists are, and what they do． It will give them an awareness and understanding of the relationship between science and our culture and an appreciation of the roles science may play in our culture． In addition, readers may learn to appreciate the relationship between scientific views and some of the values and philosophies that are pervasive in our culture．

We have tried to present in this book an accurate and up-to-date picture of the scientific community and the people who populate it．That population has in recent years come to comprise more and more women．This increasing role of women in the scientific subculture is not an unique incident but, rather, part of the trend evident in all segments of society as more women enter traditionally male-dominated fields and make significant contributions． In discussing these changes and contributions, however, we are faced with a language that is implicitly sexist, one that uses male nouns or pronouns in referring to unspecified individuals．

To offset this built-in bias, we have adopted the policy of using plural nouns and pronouns whenever possible and, when a'bsolutely necessary, alternating he and she．This policy is far from being ideal, but it is at least an acknowledgment of the inadequacy of our language in treating half of the human race equally．

We have also tried to make the book entertaining as well as informative,Our approach is usually informal． We feel, as do many other scientists, that we shouldn't take ourselves too seriously． As the reader may observe, we see science as a delightful pastime rather than as a grim and dreary way to earn a living．

According to the passage, “scientific subculture”means ()．

A．cultural groups that are formed by scientists

B．people whose knowledge of science is very limited

C． the scientific community

D． people who make good contributions to science

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第6题

Prior to modern times, Western Europe was an underdeveloped rather than a developed re
gion.In the eleventh century China was producing two and a half times as much iron as did England and Wales together in 1640.By the twelfth century several Chinese cities had a population n equal to that of the whole contemporary England- about 1.3 million people.When the Westerners began their attack of Constantinople in 1203, they were full of respects for those high walls, those mighty towers, those rich palaces and churches, of which there were so many that no man could believe it if he had not seen them with their own eyes.

In modern times the situation was changed, thanks in large part to the profits from overseas trade and colonies, and to the settlement in new continents.Therefore, ninety percent of the world's total industrial output comes today from European origin.About two-thirds of the world's people are earning about $200 per capital every year, while the remaining one-third enjoy per capital incomes as high as $2,400 in the case of the United States.

1.In the 11th century China was___.

A.more underdeveloped than Western Europe

B.more advanced in technology than England

C.as developed as Western Europe

D.producing as much iron as Western Europe

2.Constantinople was_______.

A.a part of Western Europe

B.part of China

C.quite rich and prosperous

D.was a city with a population of 1.3 million

3.Europe became much more developed in modern times mainly by().

A.attacking Constantinople

B.making profits from foreign trade and their colonies

C.learned from the developed parts of the world and improved its technology

D.having its people form. the idea of working hard

4.It can NOT be concluded from the passage that().

A.several Chinese cities altogether had a total population of 1.3 million

B.westerners admired Constantinople for its marvelous buildings

C.Constantinople was much more developed than the invaders 'hometown

D.Americans have much higher salaries than two-thirds of the world' s people

5.Which of the following is true according to the passage？()

A.Four fifths of the world's products come from Europe

B.Ninety percent of the world's industrial output is from Europe

C.Europe began to develop when they attacked Constantinople

D.Westerners set up colonies after they became rich

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第7题

Passage TwoQuestions 26 to 30 are based on the following passage. Scientists have establis

Passage Two

Questions 26 to 30 are based on the following passage.

Scientists have established that influenza viruses taken from man can cause the disease in animals. In addition，man can catch the disease from animals. In fact，a great number of wild birds seem to carry the virus without showing any evidence of illness. Some scientists conclude that a large family of influenza viruses may have evolved in the bird kingdom，a group that has been on the earth 100 million years and is able to carry the virus without contracting the disease. These are even convincing evidence to show that virus strains are transmitted from place to place and from continent to continent by migrating birds.

It is known that two influenza viruses can recombine when both are present in an animal at the same time. The result of such recombinations is a great variety of strains constraining different H and N spikes. This raises the possibility that a human influenza virus can recombine with an influenza virus form. a lower animal to produce an entirely new spike.

Research is underway to determine if that is the way that major new strains come into being. Another possibility is that two animal influenza strains may recombine in a pig，for example，to produce a new strain which is transmitted to man.

According to the passage，scientists have discovered that influenza viruses______.

A. cause ill health in wild birds

B. do not always cause symptoms in birds

C. are rarely present in wild birds

D. change when transferred from animals to man

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第8题

Once it was considered good to keep the car engine idling a minute or two following cold s
tarts. Today, with modern technology, the opposite is true. An engine operating under road conditions will warm up faster and run more efficiently than the one that is idling. Idling just burns gas (on average, about a gallon an hour).

When you have a full tank of gas, park the car downhill. This will prevent any gas from coming out of the tank. Parking in areas of less or no sunlight helps prevent the gas from steaming that would occur if you parked in the hot sun. Your car will stay cooler, too, and that means less gas consuming work for the air conditioner once the engine is started.

Stay away from wide-track tyres if you want top mileage (汽车耗费1加仑油所行驶的路程) . Narrow-track tyres produce less friction and thus less rolling resistance. The same effect is achieved by adding three to five pounds above recommended pressure to each tyre: while this won't noticeably affect you car's sliding quality, it will increase tyre life and gas mileage.

Check tyre pressure often, especially when the weather turns cold. The difference between winter and summer tyre pressure can be as much as eight pounds. This could cost you two miles per gallon.

The main purpose of the passage is to tell us______.

A．how to drive faster

B．how to drive a car properly

C．how to make a car run smoothly

D．how to make your car consume less gas

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第9题

It was once considered a good idea to keep the car engine running on idle for a minute or two following a cold start.Today,with modern technology,the opposite is true.An engine operating under road conditions will warm up faster and run more efficiently than the one that has been idling,as this just burns up gas(on average about a gallon an hour).

If possible,when you have a full tank of gas,park the car facing downhill,as this will prevent any gas from leaking out of the tank.Parking in areas of little or no sunlight helps prevent evaporation(蒸发)of the gas which would occur if you parked in the hot sun.Your car will stay cooler,too,and this means less gas is consumed for the air conditioner once the engine is started.

Stay away from wide-track tires if you want top mileage for your dollar.Narrow-track tires produce less friction and thus rolling resistance.The same effect is achieved by adding three to five pounds above recommended pressure to each tire while this won't noticeably affect your car's mobility,it will increase the life of your tires and gas mileage.

Check tire pressure often,especially when the weather turns cold.The difference between winter and summer tire pressure can be as much as eight pounds.This could cost you two miles per gallon.

1.The main purpose of the passage is to tell us（）.

A.how expert drivers try to save gas

B.how to drive a car properly

C.how to make a car run smoothly

D.how to make your car consume less gas

2.According to the passage,keeping the engine run idly（）.

A.will just waste gas

B.will warm it up more quickly

C.will make it work more efficiently

D.is necessary in cold weather

3.Parking your car in a cool place（）.

A.will take it longer to warm up the engine

B.means less gas consumption for the air conditioner

C.prevent any gas from coming out of the tank

D.helps start your car more easily

4.Wide-track tires（）.

A.won't noticeably affect your car's sliding quality

B.can increase tire life

C.will increase rolling resistance

D.helps attain top gas mileage

5.Tire pressure changes（）.

A.when wide-track tires are used

B.when narrow-track tires are used

C.in different weather conditions

D.in different road conditions

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第10题

The best title for this passage might be______．A．Hegel，the Great German Philosoph

The best title for this passage might be______．

A．Hegel，the Great German Philosopher

B．The Learning Situation in the Modern University

C．HOW to Study at a Modern University

D．The Rapid Development of Science

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