In the atmosphere, carbon dioxide acts rather like a one-way mirror or 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 (北半球), 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 gone beyond 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 (使旋转), 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 changeable over a long term: its heat output goes up and down in cycles, the latest trend being downward.

　　  Scientists are now finding shared relations between models of solar weather interactions and the actual climate over many thousands 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 (惯性) of the earth's climate. If this is right, the warming effect of carbon dioxide might thus be serving as a useful opposed balance to the sun's fading heat .

66. It can be concluded that a concentration of carbon dioxide in the atmosphere would_________.

   A. mean a warming-up in the Antarctic

   B. raise the temperature of the earth' s surface

C. prevent the sun's rays from reaching the earth's surface

D. explain the cause of  great changes in the climate in the northern hemisphere

67.The article was written to explain ___________. 

A. the greenhouse effect

B. the solar effects on the earth

C. the causes affecting weather

D. the models of solar-weather interactions

68. 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. partly due to changes in the output of solar energy

C. possibly because the ice caps in the poles are melting

D. only due to the effect of the inertia of the earth' s climate

69. On the basis of their models, scientists believe the opinion that__________.

A. the climate of the world should be becoming cooler

B. the new Ice Age will be delayed by the greenhouse effect

C. the man-made warming effect helps to increase the solar effects

D. it will take thousands of years for the inertia of the earth's climate to take effect

70. If the assumption about the delay of a new Ice age is correct, ____________.

A. ice would soon cover the northern hemisphere

B. the greenhouse effect could work in favor of the earth

C. the best way to overcome the cooling effect would be to burn more fuels

D. the increased levels of carbon dioxide in the atmosphere could warm up the earth even more quickly

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(爆炸) were watched by scientists here on the 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(巨大的) 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(崩溃). 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 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?

1.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 visit of the comet results in wars

D. The whole mankind becomes extinct

2.Why does the author mention dinosaurs at the end of the passage?

A. Because they could only live in the warm climate

B. Because their extinction indicates future disasters

C. Because they once dominated(控制) the earth

D. Because dinosaurs and humans never live in the same age

3. In writing the passage, the author intends to ______.

A. give an accurate description of the possible disaster in the future

B. prove that humans will sooner or later be destroyed

C. warn of a possible disaster in the future

D. tell the historical development of the Earth

4.It can be concluded that the passage is most probably part of a(n) ______.

A. article of popular science      B. news report

C. research paper                      D. horror story

D
　　In the atmosphere,carbon dioxide actd rather like a one-way mirror or the glass in the roof of a greenhouse which allows the sun's rays to enter but prevents the heat from excaping.
　　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 luels 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 meters and severely flooding coastal cities.Also，the increase in atmospheric temperature would lead to great changes in the climate of the northern hemisphere(半球),psooicbly resulting in an alteration of 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 a warming on the scale that will possibly take place in the next fifty years from on burning of fuels.
　　Satellite pictures showthat 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(旋转),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 of solar weather interactions and the actual climate over many thousands 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(不活动，惰性) 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.
　　68.It can be concluded that a concentration of carbon dioxide in the atmosphere would ___.
　　　A.mean a warming - up im the Arctic
　　　B.raise the temperature of the earth's surface
　　　C.prevent the sun's rays from reaching the earth's surface
　　　D.account for great changes in the climate in the northern hemiphere
　　69.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.partly due to variations in the output of solar energy
　　　C.possibly because the ice caps in the poles are melting
　　　D.exclusively due to the effect of the inertia of the earth's climate
　　70.On the basis of their models,scientists are of the opinion that ________.
　　　A.the climate of the world should be becoming cooler
　　　B.the new Ice Age will be delayed by the greenhouse effect
　　　C.the man - made warming effect helps to increase the solar effects
　　　D.it will take thousands of years for the inertia of the earth's climate to take effect

Scientists are closely concerned with the structure of buildings and with the quality of building materials． The World health Organization （WHO) observes that the introduction of air conditioning and energy conservation （保护) measures have been accompanied by growing problems of indoor air quality． Some pollutants arise from insulation （隔音) products, some from moving cars, and others from modern housing materials． As many Europeans spend up to 90% of their lives in buildings, the health effects of the indoor climate are very important．

　　Some construction materials, including fiberboard, insulation foams and certain glues for man-made wood floor boards, for example, give out organic products such as formaldehyde （甲醛)． Heat and humidity increase the release of formaldehyde and the gas seriously harms the eyes． Paint, lacquer, etc． can also release dangerous gas into indoor air．

　　Construction materials can cause serious damage, especially when they contain asbestos（石棉）． Asbestos is naturally present in rock formations worldwide． It belongs to a family of mineral substances made up of solid, non-combustible（非易燃品） fiber． These properties make asbestos a highly sought-after construction material． As early as 1931, however, public health officers in the United Kingdom revealed the connection between breathing in asbestos dust and such diseases as lung cancer．

　　The land on which a building is sited may also contribute to pollution． Some kinds of granite or similar rocks contain traces of radium． As it breaks down, this naturally radioactive element produces some kind of radioactive gas that goes through tiny cracks in walls, floors and building materials, and makes its way into the building and the rooms． The better the homes are insulated, the more is the dangerous gas in indoor air． The main effect of this dangerous gas on health is to increase the risk of lung cancer．

1.What is the main idea of the passage?

    A．Some building materials pollute indoor air．

    B．Some factors cause indoor air pollution．

    C．Asbestos can cause lung cancer．

    D．The land on which houses are built contributes to indoor pollution．

2.Why are Europeans particularly concerned with building materials?

    A．Lots of building materials there are radioactive．

    B．They stay home up to 90% of their lives．

    C．They have a high rate of lung cancer．

    D．They spend most of their time indoors．

3.Why is asbestos a sought-after building material?

    A．It is a kind of insulation foam．

    B．Asbestos will not give out dangerous gas．

    C．This material is not easy to catch fire．

    D．It is rarely present in rock formations．

4.Why should we be careful about the land on which a building is to be sited?

    A．To determine whether the land is firm enough for a building to be sited on．

    B．To make sure that the land contains no radioactive material．

    C．To make certain that the land releases no formaldehyde or other gases．

    D．To check whether it contains any combustible materials．

So long as teachers fail to distinguish（区别, 辨认） between teaching and learning, they will continue to undertake to do for children that which only children can do for themselves. Teaching children to read is not passing reading on to them. It is certainly not endless hours spent in activities about reading．Douglas insists that “reading cannot be taught directly and schools should stop trying to do the impossible”.

　  Teaching and learning are two entirely different processes. They differ in kind and function. The function of teaching is to create the conditions and the climate that will make it possible for children to devise the most efficient system for teaching themselves to read. Teaching is also public activity. It can be seen and observed.

　  Learning to read involves all that each individual does to make sense of the world of printed language. Almost all of it is private, for learning is an occupation of the mind, and that process is not open to public observation.

　  If teacher and learner roles are not interchangeable, what then can be done through teaching that will aid the child in the quest（探索）for knowledge? Smith has one principal rule for all teaching instructions. “Make learning to read easy, which means making reading a meaningful, enjoyable and frequent experience for children.”

When the roles of teacher and learner are seen for what they are, and when both teacher and learner fulfill them properly, then much of the pressure and feeling of failure for both is eliminated(除去, 剔除). Learning to read is made easier when teachers create an environment where children are given the opportunity to solve the problem of leaning to read by reading.

The problem with the reading course as mentioned in the first paragraph is that ______.

       A．it is one of the most difficult school courses　     

       B．students spend endless hours in reading

       C．reading tasks are assigned with little guidance　

       D．too much time is spent in teaching about reading

The teaching of reading will be successful if ______.

　　A．teachers can improve conditions at school for the students

　　B．teachers can enable students to develop their own way of reading

　　C．teachers can devise the most efficient system for reading

　　D．teachers can make their teaching activities observable

According to the passage, learning to read will no longer be a difficult task when ______.

       A．children become highly motivated　　        

       B．teacher and learner roles are interchangeable

       C．teaching helps children in the search for knowledge　

       D．reading enriches children’s experience

The main idea of the passage is that ______.

　　A．teachers should do as little as possible in helping students learn to read

　　B．teachers should encourage students to read as widely as possible

　　C．reading ability is something acquired rather than taught

D．reading is more complicated than generally believed