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大学英语六级考试全真模拟试题1

网上收集 2008/1/30 12:56:47

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Part I Listening Comprehension （20 minutes）(略)
Part Ⅱ Reading Comprehension （35 minutes）

Directions: There are 4 passages in this part. Each passage is followed by some questions or unfinished statements. For each of them there are four choices mared A）, B）, C） and D）.You should decide on the best choice and mark the corresponding letter on the Answer Sheet with a single line through the center.

Passage One

Questions 21 to 25 are based on the following passage:
There are three basic ways in which individual economic units interact with one another. They are the market system, the administered system, and the traditional system.

In a market system, individual economic units are free to interact among each other in the market place. Transactions may take place through barter or money exchange. In a barter economy,real goods such as automobiles, shoes, and pizzas are traded against each other. Obviously, finding somebody who wants to trade an old car in exchange for a sailboat may not always be an easy task. Hence the introduction of money as a medium of exchange eases transactions considerably.

An alternative to the market system is administered control by some agency over all transactions. This agency will issue laws or commands as to how much each goods and service should be produced, exchanged, and consumed by each economic unit. Central planning may be one way of administering such an economy. The central plan drawn up by the government shows the amount of each commodity produced by the various firms and distributed to different households for consumption.

In a traditional society, production and consumption patterns are governed by tradition. Each person′s place with the economic system is fixed by parentage, religion, and custom. Transactions take place on the basis of tradition, too. People belonging to a certain group or caste may have an obligation to care for other persons, provide them with food and shelter, care for their health,and provide for their education. Clearly, in a system where every decision is made on the basis of tradition alone progress may be difficult to achieve.

21. What is the main purpose of the passage?
A） To explain the science of economics.
B） To outline types of economic systems.
C） To argue for the superiority of one economic system.
D） To compare barter and moneyexchange markets.
22. In the second paragraph, by which of the following could the word "real" best be replaced?
A） High quality.
B） Concrete.
C） Utter.
D） Essential.
23. According to the passage, a barter economy can lead to 
A） rapid speed of transactions
B） misunderstandings
C） inflation
D） difficulties for the traders
24. According to the passage who has the greatest degree of control on an administered system?
A） Individual households.
B） Small businesses.
C） Major companies.
D） The government.
25. Which of the following statements is true?
A） The central plan drawn up by the government is mainly based on the needs of the state as a whole.
B） The economic system in China is based on the traditional system.
C） In a market system, transactions are controlled by the government.
D） In a traditional society, economy develops very fast.

Passage Two

Questions 26 to 30 are based on the following passage:

In the atmosphere, carbon dioxide （二氧化碳） acts rather like a one-way mirror—the glass in the roof of a greenhouse which allows the sun′s rays to enter but prevents the heat from escaping.According to a weather expert′s prediction, the atmosphere will be 3℃ warmer in the year 2050 than it is today, if man continues to burn fuels at the present rate. If this warming up took place, the ice caps in the poles would begin to melt, thus raising sea level several metres and severely flooding coastal cities, Also, the increase in atmospheric temperature would lead to great changes in the climate of the northern hemisphere, possibly resulting in an alteration of the earth′s-chief food-growing zones.

In the past, concern about a man-made warming of the earth has concentrated on the Arctic because the Antarctic is much colder and has a much thicker ice sheet. But the weather experts are now paying more attention to West Antarctic, which may be affected by only a few degrees of warming: in other words, by a warming on the scale that will possibly take place in the next fifty years from the burning of fuels. Satellite pictures show that large areas of Antarctic ice are already disappearing. The evidence available suggests that a warming has taken place. This fits the theory that carbon dioxide warms the earth.

However, most of the fuel is burnt in the northern hemisphere,where temperatures seem to be falling. Scientists conclude,therefore, that up to now natural influences on the weather have exceeded those caused by man. The question is: Which natural cause has most effect on the weather?

One possibility is the variable behavior of the sun. Astronomers at one research station have studied the hot spots and "cold" spots（that is, the relatively less hot spots） on the sun.As the sun rotates, every 27.5 days, it presents hotter or "colder" faces to the earth, and different aspects to different parts of the earth. This seems to have a considerable effect on the distribution of the earth′s atmospheric pressure, and consequently on wind circulation. The sun is also variable over a long term: its heat output goes up and down in cycles, the latest trend being downward.

Scientists are now finding mutual relations between models or solar-weather interactions and the actual climate over many thousand of years, including the last Ice Age. The problem is that the models are predicting that the world should be entering a new Ice Age and it is not. One way of solving this theoretical difficulty is to assume a delay of thousands of years while the solar effects overcome the inertia of the earth′s climate. If this is right, the warming effect of carbon dioxide might thus be serving as a useful counter-balance to the sun′s diminishing heat.

26. It can be concluded that a concentration of carbon dioxide in the atmosphere would .
A） prevent the sun′s rays from reaching the earth′s surface
B） mean a warming up in the Arctic
C） account for great changes in the climate in the northern hemisphere
D） raise the temperature of the earth′s surface
27. The article was written to explain .
A） the greenhouse effect
B） the solar effects on the earth
C） the models of solarweather interactions
D） the causes affecting weather
28. Although the fuel consumption is greater in the northern hemisphere, temperatures there seem to be falling. This is .
A） mainly because the levels of carbon dioxide are rising
B） possibly because the ice caps in the poles are melting
C） exclusively due to the effect of the inertia of the earth′s climate
D） partly due to variations in the output of solar energy
29. On the basis of their models, scientists are of the opinion that .
A） the climate of the world should be becoming cooler
B） it will take thousands of years fro the inertia of the earth′s climate to take effect
C） the manmade warming effect helps to increase the solar effect
D） the new Ice Age will be delayed by the greenhouse effect
30. If the assumption about the delay of a new Ice Age is correct, .
A）the best way to overcome the cooling effect would be to burn more fuels
B） ice would soon cover the northern hemisphere
C） the increased levels of carbon dioxide in the atmosphere could warm up the earth even more quickly
D）the greenhouse effect could wo

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