GWD19 推不出来了 哎 谢谢大家

renaultboy

In Patton City, days are categorized as having heavy rainfall (more than two inches), moderate rainfall (more than one inch, but no more than two inches), light rainfall (at least a trace, but no more than one inch), or no rainfall.In 1990, there were fewer days with light rainfall than in 1910 and fewer with moderate rainfall, yet total rainfall for the year was 20 percent higher in 1990 than in 1910.

If the statements above are true, then it is also possible that in Patton City

A.the number of days with heavy rainfall was lower in 1990 than in 1910

B.the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910

C.the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910

D.the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910

E.the average amount of rainfall per month was lower in 1990 than in 1910

答案是A  我推不出来 谢谢NN 解答

peter3008

“已知：heavy rainfall > 2 inches； 2>=moderate rainfall > 1； 0<light rainfall<=1

　　且 1990年小雨和中雨的天数都比1910少，然而1990年全年的降雨量还比1910多，那就只能是1990年的大雨天数比1910多，一般我们都会这样的预估，但选项恰恰没有该项。迷茫中，看到了D，误以为找到了救星，正好落在了出题者的陷阱之中。

　　细看该题所问“If the statements above are true， then it is also possible that in Patton City”，原来并非是由原文推出选项的导出题，而是一道怪题；只要是“可能的”项就是正确的。换句话说，依据原文，有四个选项是绝不可能的，只有一个是可能的。

　　那再看D，在1990年中雨天数比1910少的情况下，其降雨量可以超过1910的2倍吗？绝不可能——因为2>=moderate rainfall > 1，即最大的中雨量不超过最小的中雨量的2倍，也就是：即便1990的中雨天每次都是最大量，而1910的中雨量每次都是最小量，那么D都不能成立。

　　而B与C明显与已知条件矛盾(“1990年小雨和中雨的天数都比1910少”)

　　而E与“1990年全年的降雨量还比1910多”冲突

　　看来也就A有希望了；但A与我们的预估相反。

   但A的确是可能的，这一点人间惆怅客和其楼上的新浪网友都有很好的解释。说个最极端的情况，1990年只下了一天雨，那是一场万年不遇的亿寸豪雨，其降雨量可以远远超过1910年的天天小雨、中雨或so so 大雨。一天就超过365天这有什么不可能的呢？“
引用：http://ieol.chsi.com.cn/chuguo/kszx/gmat/200902/20090219/17617687.html

renaultboy

谢谢 呵呵

兔子和羊

peter3008 发表于 2010-2-25 07:22
“已知：heavy rainfall &gt; 2 inches； 2&gt;=moderate rainfall &gt; 1； 0&lt;light rainfall&lt;=1　　且 1990年小雨 ...

谢谢你，解释的太好了，我茅塞顿开~！