阅读理解（第3l～45题，每题3分，共15分）

　　请根据短文内容，为每题确定1个最佳选项。

Arctic Melt

　　Earth's North and South Poles ale famous for being cold and icy．Last year，however，theamount of ice in the Arctic Ocean feU t0 a record low．

　　Normally，ice builds in Arctic waters around the North Pole each winter and shrinks during thesummer．But for many years，the amount of ice left by the end of summer has been declining．

　　Since 1979，each decade has seen an 11．4 percent drop in end of summer ice cover．Between1981 and 2000，ice in the Arctic lost 22 percent of its thickness，becoming 1．13 meters thinner．

　　Last summer，Arctic sea ice reached its skimpiest levels yet．By the end of summer 2007，theice had shrunk to cover iust 4．2 million square kilometers．That's 38 percent less area than the average cover at that time of year．And it's a very large 23 percent below the previous record low，whichwas set just 2 years ago．This continuing trend has scientists concerned．

　　There may be several reasons for the ice melt，says Jinlun Zhang，an oceanographer at the University of Washington at Seattle．Unusually strong winds blew through the Arctic last summer．Thewinds pushed much of the ice out of the central Arctic．leaving a large area of thin ice and open water．

　　Scientists also suspect that fewer clouds cover the Arctic now than in the past．Clearer skies allow more sunlight to reach the ocean．The extra heat warnls both the water and the atmosphere．Inparts of the Arctic Ocean last year，surface temperatures were 3．5℃ warmer than average and 1．5℃warmer than the previous record high．

　　With both air and water getting warmer，the ice is melting from both above and below．In someDarts 0f the Beaufort Sea，north of Alaska and western Canada，ice that measured 3．3 meters thickat the beginning of the summer measured just 50 centimeters by season's end．

　　The new measurements suggest that melting is far more severe than scientists have seen by justlooking at ice cover from above，says Donald K．Perovich，a geophysicist at the U．S．Army ColdRegions Research and Engineering Laboratory in Hanover，N．H．

　　Some scientists fear that the Arctic is stuck in a warming trend from which it may never recover．

　　31．Which of the following is closest in meaning to the word"build"in the first sentence of the second paragraph?

　　A．construct

　　B．extend

　　C．create

　　D．expand

　　32．What is the ice cover in the Arctic by the end of 2007 summer?

　　A．4．2 million square kilometers

　　B．11．4 million square kilometers

　　C．1．13 million square kilometers

　　D．38 million square kilometers

　　33．What are the reasons for the ice melting according to the scientists?

　　A．strong winds and clear skies

　　B．long summer and short winter

　　C．open water and thin ice

　　D．light clouds and light winds

　　34．Why is the ice melting from both above and below?

　　A．Because extra heat warms the air．

　　B．Because extra heat warms the water．

　　C．Because the temperature above the water is higher．

　　D. Rnth A and B．

　　35．What can be a possible title for the passage?

　　A．What are scientists looking for in the Arctic Ocean?

　　B．What are scientists doing in the Arctic Ocean?

　　C．Why are scientists worrying about the Arctic Ocean?

　　D．Why are scientists interested in the Arctic Ocean?

　　参考答案及解析

　　31．D [解析]本句话的译文为每年冬天北极附近的北冰洋开始结冰，build为结冰的意思，expanel有容积扩张的意思，所以与build相符；而construct为修筑、建筑的意思，所以不能选。

　　32．A [解析]原文为by the end of summer 2007，the ice had shrunk to cover just．4．2 million square kilometers．

　　33．A[解析]第五段的最后一句话和第六段的第一、二句话说明了科学家们推测冰川融化的原因，一为强风；二为较少的云，即clear skies。

　　34．D[解析]据第七段的第一句话with both air antl water getting warmer可知。

　　35．C [解析]本文讲述的科学家们担心气温上升、冰川融化，最后一句话体现了主旨，所以选C。