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

A desert is a beautiful land of silence and space. The sun shines, the wind blows, and time and space seem endless. Nothing is soft. The sand and rocks are hard, and many of the plants even have hard needles instead of leaves.

The size and location(分布) of the world’s deserts are always changing. Over millions of years, as climates change and mountains rise, new dry and wet areas develop. But within the last 100 yeas, deserts have been growing at a frightening speed. This is partly because of natural changes, but the greatest makers are humans.

Humans can make deserts, but humans can also prevent their growth. Algeria Mauritania is planting a similar wall around Nouakchott, the capital. Iran puts a thin covering of petroleum(石油) on sandy areas and plants trees. The oil keeps the water and small trees in the land, and men on motorcycles(摩托车) keep the sheep and goats away. The USSR and India are building long canals to bring water to desert areas.

In this passage, “needles” refers to _______.

A. small, thin pieces of steel.

B. long, thin pieces of branches.

C. small pointed growth on the stem(茎) of a plant.

D. small, thin pieces of sticks.

Which of the following is NOT true?

A. The greatest desert makers are humans.

B. There aren’t any living things in the deserts.

C. Deserts have been growing quickly.

D. The size of the deserts is always changing.

People in some countries are fighting a battle against _______.

A. the growth of deserts B. the disappearance of desert plants

C. natural changes  D. congenital climate

We can guess that Mauritania and Algeria belong to _______.

A. Asian countries 　　　　       B. American countries

C. European counties　　　 D. African countries

Choose the sentence which best gives the main idea of the passage.

A. The deserts of the world are always changing.

B. Man is to take measures to control the growth of the world’s deserts.

C. Deserts are lands of silence and space.

D. Deserts have grown at a fast pace in the past 10 years.

Hoffman，40，a former senior vice president of a financial company，had what she describes as “one of those extreme jobs.” “I loved working,” she says. But her career path reached a crossroad when her second child was born，and she left her job in February 2007. Hoffman is one of many people who have left the work force to take a break，but she has a position as a consultant．She has described this type of career detour(绕路) ----- which is more common for women than for men—as “off- ramping．” Typically it occurs when the balancing act of parenting and work becomes too tough．
A study by the center found that more than 90 percent of women who off-ramp want to on-ramp back into the work force eventually．But making the transition back to work is rarely easy，and it is even harder in this economic climate of layoffs and hiring freezes.
Considering some of the obstacles faced by on- rampers , a three-day program called “Greater Returns：Restarting Your Career” was held at Columbia University. The goal of the three days was to have them walk away with a big shot of confidence.
　According to one school of thought, women looking to make a comeback might even have an advantage in the current economy，especially if they are looking for part-time or consultant positions that do not offer benefits. And a majority of on-rampers are women with extensive working experiences that could give them a slight advantage over less-experienced competition．
　“You absolutely cannot be defensive about why you off-ramped,” Ms Hoffman says, “ defensive” would have put her into a hard situation if the Greater Returns program had had not taught her how to describe the years she spent at home．“I now feel confident talking to an employer and saying，‘ Yes，I have been out of the work force，but here is where I can make significant contributions.’”
【小题1】What is the best title for the passage?

Department stores sell ready- to-wear clothing, which is also called ready-made clothing. Such clothing is made in fixed sizes. Those people who find that ready-made clothing fits them well can save money by buying it. Most often, people do not fit exactly into a producer’s size. Their clothing must be altered to make it fit better. However, most alterations are not very expensive. The small cost of most alterations means that ready-made clothing can meet the needs of most customers.
Those who can afford it often get someone to design and make their clothing. Such clothing is called custom-made. The person who makes it measures the customer, and then sews it so that it fits perfectly. Alterations are not needed. Custom-made clothing is largely sewn by hand, has better quality, better material, and is of the style you have chosen. Of course, it costs much more than ready-to-wear clothing. You need to pay the difference for the special fitting and better skill that you are receiving. This often means that you spend double or more than you would for a ready-made garment.
Custom-made clothing is not always that much better than ready-made clothing. It costs more partly because only one garment has been made, just for you. Companies that produce ready-made products make thousands of garments at a time. This means they can buy large quantities of material. Workers cut each size by the hundreds. Companies work out ways to make the garments quickly by machine and pay workers according to their skill. Thus they can sell the finished products at a low price while still making money. Most of the clothing sold in the United States is made in this way. Customers gain from the lower prices which are made possible by mass production. It may or may not give them high quality.
【小题1】 According to the passage, people who buy ready-made clothing ______.