The idea of a fish being able to generate electricity strong enough to light lamp bulbs--or even to run a small electric motor--is almost unbelievable, but several kinds of fish are able to do this. Even more strangely, this curious power has been acquired in different ways by fish belonging to very different families. Perhaps the best known are the electric rays, or torpedoes(电鳐), of which several kinds live in warm seas. They possess on each side of the head, behind the eyes, a large organ consisting of a number of hexagonal shaped cells rather like a honeycomb. The cells are filled with a jelly-like substance, and contain a series of flat electric plates. One side, the negative side, of each plate, is supplied with very fine nerves, connected with a main nerve coming from a special part of the brain. Current passes from the upper, positive side of the organ downwards, to the negative, lower side. Generally it is necessary to touch the fish in two places, completing the circuit, in order to receive a shock. The strength of this shock depends on the size of the fish, but newly born ones only about 5 centime-tres across can be made to light the bulb of a pocket flashlight for a few moments, while a fully grown torpedo gives a shock capable of knocking a man down, and, if suitable wires are connected, will operate a small electric motor for several minutes. Another famous example is the electric eel. This fish gives an even more powerful shock. The system is different from that of the torpedo in that the electric plates run longitudinally(纵向) and are supplied with nerves from the spinal(脊骨) cord. Consequently, the current passes along the fish from head to tail. The electric organs of these fish are really altered muscles and like all muscles are apt (likely) to tire, so they are not able to produce electricity for very long. The power of producing electricity may serve these fish both for defence and attack.It can be seen from the passage that（）.

第1题

The main idea of the third paragraph is that______.A．a mature torpedo is capable of produc

The main idea of the third paragraph is that______.

A．a mature torpedo is capable of producing enough electricity to knock down a man

B．the mass of the fish decides the intensity of electric power it generates

C．the strength of shock given by a young electric ray can only light the bulb of a pocket flashlight

D．to make full use of the energy produced by electric fish, suitable wires should be available

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第2题

Passage Five The Northern Pike is a very bad fish. It is a big, hungry fish, and swallows

Passage Five

The Northern Pike is a very bad fish. It is a big, hungry fish, and swallows little fish such as trout and perch. Many Northern Pikes live in Lake Davis. They are killing all the smaller fish in the lake. The Northern Pike are a serious threat to the lake because they eat all the smaller fish. Soon, all other species of fish in the lake will be killed off. This is not healthy for the environment.

Experts are afraid that the Northern Pike will swim out of Lake Davis through many smaller rivers that feed into the lake. They could spread all over the country and damage many other water environments. If that happens, it would be too late to stop the Northern Pike.

For ten years, officials have been trying to remove the Northern Pike from Lake Davis. They haw. tried using nets, explosives and poisons. However, the Northern Pike population is still doing well in Lake Davis. Many people do not like the idea of using poison to kill the fish. They worry that the poi- sons are bad for humans who use the water. No trace of the poisons has ever been found in local wells, however.

Scientists are going to try the poison again. This time, they will drain the lake before they add the poison to the water. A public hearing will be held to talk about the problem.

52. Why are some people against the use of poisons to kill Northern Pike？

A. Fishermen will be poisoned too.

B. The poisons are expensive.

C. They think that wells will be polluted.

D. The lake will become unsafe.

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第3题

The idea of a fish being able to generate electricity strong enough to light lamp bulbs--o

r even to run a small electric motor--is almost unbelievable, but several kinds of fish are able to do this. Even more strangely, this curious power has been acquired in different ways by fish belonging to very different families.

Perhaps the best known are the electric rays, or torpedoes (电鱼), of which several kinds live in warm seas. They posses on each side of the head, behind the eyes, a large organ consisting of a number of hexagon- al shaped cells rather like a honeycomb. The cells are filled with a jelly-like substance, and contain a series of flat electric plates. One side, the negative side, of each plate, is supplied with very fine nerves, connected with a main nerve coming from a special part of the brain. Current passes from the upper, positive side of the organ downwards to the negative, lower side. Generally it is necessary to touch the fish in two places, completing the circuit, in order to receive a shock.

The strength of this shock depends on the size of the fish, but newly born ones only about 5 centimeters across can be made to light the bulb of a pocket flashlight for a few moments, while a fully grown torpedo gives a shock capable of knocking a man down, and, if suitable wires are connected, will operate a small electric motor for several minutes.

Another famous example is the electric eel. This fish gives an even more powerful shock. The system is different from that of the torpedo in that the electric plates run longitudinally (纵向) and are supplied with nerves from the spinal(脊骨)cord. Consequently, the current passes along the fish from head to tail. The electric organs of these fish are really altered muscles and like all muscles are apt (likely) to tire, so they are not able to produce electricity for very long.

The power of producing electricity may serve these fish both for defence and attack.

It can be seen from the passage that ______. ()

A．the capacity to generate electricity is the distinctive characteristic of the fish

B．the current travels in an upward direction from the positive side to negative side in torpedo's electric cells

C．some fish can produce enough electricity to drive a number of electric motors

D．the torpedo's electric cells have a shape with six sides

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第4题

Babies love chocolate and sometimes they also eat the paper around it.My cat enjoys a

meal of good，thick paper，old letters, for example.She doesn't like newspapers very much.

Of course，the best paper comes from wood.Wood comes from trees，and trees are plants.Vegetables and fruit and plants too，and we eat a lot of them.So can we also eat wood and paper？

Scientists say，"All food comes in some way from plants." Well，is that true？ Animals eat grass and grow fat.Then we eat their meat.Little fish eat little sea-plants; then bigger fish swim along and eat the...Chickens eat bits of grass and give us...Think for a minute.What food does not come from plants in some way？

Scientists can do wonderful things with plants.They can make food just like meat and cheese.And they can make it without the help of animals.It is very good food too.Now they have begun to say，"We make our paper from wood.We can also make food from wood.The next thing is not very difficult." What is the next thing？ Perhaps it is-food from paper.Scientists say，"We can turn paper into food.It will be good，cheap food too; cheaper than meat or fish or eggs."

So please keep your old books and letters.Don't feed them to your cat.) One day，soon，they will be on your plate.There is nothing like a good story for breakfast.

1、The best paper come from Wood.()

2、From the passage，we can infer 推断) thatfew kinds of food do not come from plants in some way.()

3、The main idea of the passage is all food comes from plants in some way.()

4、The writer asks us to keep our old books and letters because we can make food from them soon.()

5、The best title for the passage is " Food from Plants ".()

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第5题

To swim across the English Channel takes at least nine hours. It' s a hard work and it mak

es you short of breath. To fly over the Channel takes only twenty minutes (as long as you' re not held up at the airport), but it' s an expensive way to travel. You can travel by hovercraft if you don' t mind the noise, and that takes forty minutes. Otherwise you can go by boat, if you forget your sea-sickness ills. All these means of transport have their problems and the weary(不耐烦的) traveler often dreams of being able to drive to France in his own car. "Not possible", you say. Well, wait a minute. People are once again considering the idea of a Channel tunnel or bridge.

This time, the Greater London Council is looking into the possibility of building a Channel link straight to London. (79) A bridge would cost far more than a tunnel, but you would be able to go by rail or by car on a bridge, whereas a tunnel would provide a rail link only.

Why is this idea being discussed again？ Is Britain becoming more conscious of the need for links with Europe as a result of joining the EEC(欧共体) ？ Well, perhaps. The main reason, though, is that a tunnel or bridge would reach the twenty square kilometers of London' s disused dockland(船坞地). A link from London to the continent would stimulate trade and re-vitalize(使…各新有活力) the port, and would make London a main trading center in Europe. (80)With a link over the Channel, you could buy your fish and chips in England, and be able to eat them in France while they were still warm!

Which of the following statements is TRUE？

A．Swimming across the Channel takes less than four hours.

B．The idea of a Channel tunnel or bridge is a very new one.

C．It is considered to be more difficult to swim across the channel than any other means.

D．A tunnel or bridge would only reach as far as the coast.

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第6题

When prehistoric man arrived in new parts of the world, something strange happened to the

large animals: they suddenly became extinct. Smaller species survived. The large, slow-growing animals were easy game, and were quickly hunted to extinction. Now something similar could be happening in the oceans.

That the seas are being overfished has been known for years. What researchers such as Ransom Myers and Boris Worm have shown is just how fast things are changing. They have looked at half a century of data from fisheries around the world. Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time. According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) in a new fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then.

Dr. Worm acknowledges that these figures are conservative. One mason for this is that fishing technology has improved. Today's vessels can find their prey using satellites and sonar, which were not available 50 years ago. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes. In the early days, too, longlines would have been more saturated with fish. Some individuals would therefore not have been caught, since no baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past. Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around now.

Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. They believe the data support an idea current among marine biologists, that of the "shifting baseline". The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past. That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels. Most fisheries are well below that, which is a bad way to do business.

The extinction of large prehistoric animals is noted to suggest that ______.

A．large animals were vulnerable to the changing environment

B．small species survived as large animals disappeared

C．large sea animals may face the same threat today

D．slow-growing fish outlive fast-growing ones

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第7题

We have no idea about when men first began to use salt, but we do know that it has been us

ed in many different ways throughout the history.

For example, it is recorded in many history books the people who lived over three thousand years ago ate salted fish. Thousands of years ago in Egypt, salt was used to preserve the dead.

In some periods of history, a person who stole salt was thought to have broken the law. Take the eighteenth century for an example, if a person was caught stealing salt, he would be thrown into prison. History also records that only in England about ten thousand people were put into prison during that century for stealing salt! About one hundred and fifty years ago, in the year 1553, if a man took more than his share of salt, he would be thought to have broken the law and would be seriously punished. The offender' s ear was cut off.

Salt was an important item on the dinner table of a king. It was always placed in front of the king when he sat down to eat. Important guests at the king' s table were seated near the salt. Less important guests were given seats farther away from it.

Thousands of years ago in Egypt, salt was used ______.

A．to punish people who had broken the law

B．to keep dead bodies from decay

C．to keep fish alive

D．to make chemicals

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第8题

We have no idea as to when men began to use salt, but we do know that it has been used m m

any different ways throughout the history.

For example, it is recorded in many history books that people who lived over 3000 years ago ate salted fish. Thousands of years ago in Egypt, salt was used to preserve the dead.

In some periods of history, a person who stole salt was thought to have broken the law. Take the eighteenth century for example, if a person was caught stealing salt, he would be thrown into prison. History also records that only in England about ten thousand people were put into prison during that century for stealing salt! About 450 years ago, in the year 1553, if a man took more than his share of salt, he would be thought to have broken the law and would be seriously punished. The offender's ear was cut off.

Salt was an important item on the dinner table of a king. It was always put in front of the king when he sat down to eat. Important guests at the king's table were seated near the salt. Less important guests were given seats farther away from it.

Thousands of years ago in Egypt salt was used ______.

A．to punish people who had broken the law

B．to keep dead bodies from decay

C．to keep fish alive

D．to make chemicals

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第9题

Text 3 When prehistoric man arrived in new parts of the world, something strange happened

Text 3

When prehistoric man arrived in new parts of the world, something strange happened to the large animals. They suddenly became extinct. Smaller species survived. The large, slow-growing animals were easy game, and were quickly hunted to extinction. Now something similar could be happening in the oceans.

That the seas are being overfished has been known for years. What researchers such as Ransom Myers and Boris Worm have shown is just how fast things are changing. They have looked at half a century of data from fisheries around the world. Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time. According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) in a new fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then.

Dr. Worm acknowledges that the figures are conservative. One reason for this is that fishing technology has improved. Today’s vessels can find their prey using satellites and sonar, which were not available 50 years ago. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes. In the early days, too, longlines would have been more saturated with fish. Some individuals would therefore not have been caught, since no baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past. Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around now.

Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. They believe the data support an idea current among marine biologists, that of the “shifting baseline.” The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past. That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels. Most fisheries are well below that, which is a bad way to do business.

31. The extinction of large prehistoric animals is noted to suggest that ________.

[A] large animal were vulnerable to the changing environment

[B] small species survived as large animals disappeared

[C] large sea animals may face the same threat today

[D] slow-growing fish outlive fast-growing ones

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第10题

"In every known human society the male's needs for achievement can be recognized... In a g

reat number if human societies men's sureness of their sex role is tied up with their right, or ability, to practice some activity that women are not allowed to practice. Their maleness in fact has to be underwritten by preventing women from entering some field or performing some feat."

This is the conclusion of the anthropologist Margaret Mead about the way in which the roles of men and women in society should be distinguished.

If talk and print are considered it would seem that the formal emancipation of women is far from complete. There is a flow of publications about the continuing domestic bondage of women and about the complicated system of defences which men have thrown up around their hitherto accepted advantages, taking sometimes the obvious form. of exclusion form. types of occupation and sociable groupings; and sometimes the more subtle form. of automatic doubt of the seriousness of women's pretensions to the level of intellect and resolution that men, it is supposed, bring to the business of running the world.

There are a good many objective pieces of evidence for the erosion of men's status. In the first place, there is the widespread postwar phenomenon of the women Prime Minister, in India, Sri Lanka and Israel.

Secondly, there is the very large increase in the number of women who work, especially married women and mothers of children. More diffusely there ate the increasingly numerous convergences between male and female behaviour: the approximation to identical styles in dress and coiffure, the sharing if domestic tasks, and the admission of women to all sorts of hitherto exclusively male leisure-time activities.

Everyone carries round with him a fairly definite idea of the primitive or natural conditions of human life. It is acquired more by the study of humorous cartoons than of archaeology, but that does not matter since it is not significant as theory but only as an expression of inwardly felt expectations of people's sense of what is fundamentally proper in the differentiation between the roles of the two sexes. In this rudimentary natural society men go out to hunt and fish and to fight off the tribe next door while women keep the fire going. Amorous initiative is firmly reserved to the man, who sets about courtship with a club.

The phrase "men's sureness of their sex role" in the second line, first paragraph suggests that they ______.

A．are confident in their ability to charm women

B．take the initiative in courtship

C．have a clear idea of what is considered "manly"

D．tend to be more immoral than women are

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第11题

By the mid-nineteenth century, the term "ice-box" had entered the American language, but i

ce was still only beginning to affect the diet of ordinary citizens in the United States. The ice trade grew with the growth of cities. Ice was used in hotels, taverns, and hospitals, and by some forward-looking city dealers in fresh meat, fresh fish, and butter. After the Civil War (1861- 1865), as ice was used to refrigerate freight cars, it also came into household use. Even before 1880, half the ice sold in New York, Philadelphia, and Baltimore, and one-third of that sold in Boston and Chicago, went to families for their own use. This had become possible because a new household convenience, the ice-box, a precursor of the modern refrigerator, had been invented. Making an efficient ice-box was not as easy as we might now suppose. In the early nineteenth century, the knowledge of heat, which was essential to a science of refrigeration, was rudimentary. The commonsense notion that the best ice-box was one that prevented the ice from melting was of course mistaken, for it was the melting of ice that performed the cooling. Nevertheless, early efforts to economize ice included wrapping the ice in blankets, which kept the ice from doing its job. Not until near the end of the nineteenth century did inventors achieve the delicate balance of insulation and circulation needed for an efficient ice-box.

But as early as 1803, an ingenious Maryland farmer, Thomas Moore, had been on the right track. He owned a farm about twenty miles outside the city of Washington, for which the village of Georgetown was the market center. When he used an ice-box of his own design to transport his butter to market, he found that customers would pass up the rapidly melting stuff in the tubs of his competitors to pay a premium price for his butter, still fresh and hard in neat, one-pound bricks. One advantage of his ice-box, Moore explained, was that farmers would no longer have to travel to market at night in order to keep their produce cool.

What is the main idea of this passage？

A．The influence of ice on the diet.

B．The transportation of goods to market.

C．The development of refrigeration.

D．Sources of the term "ice-box".

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