Many new workers _____ trained and in two months they will _____ to build a new railway.

　　A.are; be sending 　　　　　　B.are being; be sent

Many new workers _____ trained and in two months they will _____ to build a new railway.

　　A.are; be sending 　　　　　　  B.are being; be sent

　　C.are; send 　　　　　　　　　       D.will be; be to send

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

C
　　The curtain on the 2008 US presidential election finally rose last month as Requblican Senator(参议员) John McCain and Democratic Senator Barack Obama were formally selected as candidates of the two major parties.This may be one of the hardest decisions voters have to make between two appealing candidates.The big question for voters,as they face both an economic downturn and international threats,is :who will they elect? A young first - term senator promising change and new ideas,or a longtime senator with strong military experience and a reputation as a maverick(特立独行的人)？
　　American voters have never seen a candidate quite like Obama.He has a white mother from the US and a black fater from Kenya who left the family when Obama was very young.He spent part of his youth in Indonesia.
　　However,McCain has a very different life story.
　　He grew up in a Navy family and was a daring pilot during the Vietnam War in the 1960s. When Obama was in kindergarten in Indonesia,McCain's plane was shot down over Ietenam and he became a prisoner of war.McCain could have been set free if he disowned America but he refused and so was held for five years.
　　"We need a president who is very,very old,"McCain joked at his age as many others do.If elected,he would be 72 when he takes office and the oldest man to step in.
　　So in the end,the election may depend on several factors that are hard to judge:Will Obama's race matter to a significant number of voters ? Will workingclass whites who tended to support his primary (党内初选) oponent,Hillary Clinton,vote for Obama? And perhaps most important of all,will uncertain voters be more attracted to Obama's vision or to McCain's experience?
　　Whatever happens,one thing is clear,however:Whoever walks into the White House on January 20,2009,will find huge challenges waiting for him in the Oval Office,both at home and abroad.
　　64.______makes the result of the election hard to predict.
　　　A.Whether working class whites care about Obama's inexperience
　　　B.The economic trouble the country now faces
　　　C.Who uncertain voters will finally decide to vote for
　　　D.McCain being too old to govern the country
　　65.The appeal in Obama as a presidential candidate lies in _________
　　　A.his multi - cultural background
　　　B.his belife in tradition
　　　C.his inexperience in politics
　　　D.his fantastic promises
　　66.The word "disown" in Paragraph 6 means closest to ______.
　　　A.flee from
　　　B.turn his back on
　　　C.not keep it private
　　　D.expose secrets about
　　67.The challenges that will face the new preident______.
　　　A.are not mentioned in the text
　　　B.include buklding a strong party and a friendly image
　　　C.refer to the problems of immigrants and economy
　　　D.refer to the problems of economy amd international relations