8．Half of the world's population is affected by Asian monsoons （季风），but monsoons are difficult to predict．American researchers have put together a 700-year record of the rainy seasons，which is expected to provide guidance for experts making weather predictions
Every year，moist （潮湿的） air masses，known as monsoon，produce large amounts of rainfall in India，East Asia，Northern Australia and East Africa．All this wet air is pulled in by a high pressure area over the Indian Ocean and a low pressure area to the south．
According to Edward Cook，a weather expert at Columbia University in New York，the complex nature of the climate systems across Asia makes monsoons hard to predict．In addition，climate records for the area are too recent and not detailed enough to be of much use．Therefore，he and a team of researchers spent more than fifteen years traveling across Asia，looking for trees old enough to provide long-term records．They measured the rings，or circles，inside thousands of ancient trees in more than 300 places．
Rainfall has a direct link to the growth and width of rings on some kinds of trees．The researchers developed a document they are calling a Monsoon Asia Drought Atlas．It shows the effect of monsoons over seven centuries，beginning in the 1300s．
Professor Cook says the tree-ring records show periods of wet and dry weather．"If the monsoon basically fails or is a very weak one，the trees affected by monsoons at that location might put on a very narrow ring．But if the monsoon is very strong，the trees affected by that monsoon might put on a wide ring for that year．So，the wide and narrow ring widths of the chronology that we developed in Asia provide us with a measure of monsoon variability．"With all this information，researchers say they can begin to improve computer climate models for predicting the behavior of monsoons．
"There has been widespread famine and starvation and human dying in the past in large droughts．And on the other hand，if the monsoon is particularly heavy，it can cause extensive flooding．"said Eugene Wahl，a scientist with America's National Oceanic and Atmospheric Administration．"So，to get a sense of what the regional moisture patterns have been，dryness and wetness over such a long period of time in great detail，I would call it a kind of victory for climate science．"
50．What's the passage mainly about？D
A．The effects of Asian monsoons．
B．The necessity of weather forecast．
C．The achievements of Edward cook．
D．A breakthrough in monsoon prediction．
51．It is difficult for experts to predict Asian monsoons becauseB．
A．it is hard to keep long-term climate records．
B．they are formed under complex climate systems．
C．they influence many nations．
D．there is heavy rainfall in Asia．
52．What can be inferred from the passage？A
A．Long and detailed climate records can offer useful information for monsoon research．
B．The Monsoon Asia Drought Atlas has a monsoon record for about 1，300 years．
C．The trees affected by monsoon grow fast if the monsoon is weak．
D．The rainfall might be low although the monsoon is strong in monsoon-affected areas．
53．According to Professor Cook，the rings of the treesC．
A．determine the regional climate．
B．have a great influence on the regional climate．
C．offer people information about the regional climate．
D．reflect all kinds of regional climate information．
54．What do we know about the research according to Eugene Wahl？A
A．It is a great achievement in climate science．
B．It should include information about human life in the past．
C．It has analysed moisture models world wide，
D．It will help people prevent droughts and floods．
55．Which of the following best describes the tone of this passage？A
A．Matter-of-fact B．Pessimistic C．Humorous D．Friendly．
分析 文章重点讲述了Edward Cook的科学调查报告的过程及结果，结果表明季风预测有了突破性进展
解答 50．答案是D．主旨大意题．根据文章倒数第二段最后一句"With all this information，researchers say they can begin to improve computer climate models for predicting the behavior of monsoons．"文章重点讲述了Edward Cook的科学调查报告的过程及结果，结果表明季风预测有了突破性进展．
51．答案是B．细节理解．根据the complex nature of the climate systems across Asia makes monsoons hard to predict．可知复杂的是其难以预测的主要原因，所以答案是B．
52．答案是A．推理判断题．根据文中句子"In addition，climate records for the area are too recent and not detailed enough to be of much use"太短不够详细的记录不利于我们预测疾风，也就是说长期的详细记录有利于我们研究季风，可推知答案是A．
53．答案是C．细节理解题，根据文中第五段"Professor Cook says the tree-ring records show periods of wet and dry weather．"If the monsoon basically fails or is a very weak one，the trees affected by monsoons at that location might put on a very narrow ring．But if the monsoon is very strong，the trees affected by that monsoon might put on a wide ring for that year．So，the wide and narrow ring widths of the chronology that we developed in Asia provide us with a measure of monsoon variability"可知树木的年轮可以告诉我们气候的变化情况，所以答案选C．
54．答案是A．推理判断题，根据最后一段句子"There has been widespread famine and starvation and human dying in the past in large droughts．And on the other hand，if the monsoon is particularly heavy，it can cause extensive flooding．"said Eugene Wahl"可知这一发现作用巨大，在气候科学方面是一个巨大的成就，所以答案选A．
55．答案是A．推理判断题．本文主要运用了摆事实讲道理的方法来讲述科学原理，用一种很平和的实事求是的语调来讲述文中原理，所以答案选A．
点评 阅读理解题测试考生在阅读基础上的逻辑推理能力，要求考生根据文章所述事件的逻辑关系，对未说明的趋势或结局作出合理的推断；或根据作者所阐述的观点理论，对文章未涉及的现象、事例给以解释．考生首先要仔细阅读短文，完整了解信息，准确把握作者观点．
