[求助]1997年阅读题第30题

Question 29-39

  Large animals that inhabit the desert have evolved a number of adaptations for reducing the effects of extreme heat. One adaptation is to be light in color, and to reflect rather than absorb the Sun's rays. Desert mammals also depart from the normal mammalian practice of maintaining a constant body temperature. Instead of trying to keep down the body temperature deep inside the body, which would involve the expenditure of water and energy, desert mammals allow their temperatures to rise to what would normally be fever height, and temperatures as high as 46 degrees Celsius have been measured in Grant's gazelles. The overheated body then cools down during the cold desert night, and indeed the temperature may fall unusually low by dawn, as low as 34 degrees Celsius in the camel. This is an advantage since the heat of the first few hours of daylight is absorbed in warming up the body, and an excessive buildup of heat does not begin until well into the day.

  Another strategy of large desert animals is to tolerate the loss of body water to a point that would be fatal for non-adapted animals. The camel can lose up to 30 percent of its body weight as water without harm to itself, whereas human beings die after losing only 12 to 13 percent of their body weight. An equally important adaptation is the ability to replenish this water loss at one drink. Desert animals can drink prodigious volumes in a short time, and camels have been known to imbibe over 100 liters in a few minutes. A very dehydrated person, on the other hand, cannot drink enough water to rehydrate at one session, because the human stomach is not sufficiently big and because a too rapid dilution of the body fluids causes death from water intoxication. The tolerance of water loss is of obvious advantage in the desert, as animals do not have to remain near a water hole but can obtain food from grazing sparse and far-flung pastures. Desert-adapted mammals have the further ability to feed normally when extremely dehydrated, it is a common experience in people that appetite is lost even under conditions of moderate thirst.

B30.    According to the passage, why is light coloring an advantage to large desert animals?

有疑问

(A)
                It helps them hide from predators.

(B)  It does not absorb sunlight as much as dark colors.

(C)
                It helps them see their young at night

(D)
                It keeps them cool at night.

这道题我用排除法做的,选B

但是,还是觉得B答案有点奇怪

整篇文章没提到,dark colors啊.

属于托福的出题思路?!

原文第二句就说：One adaptation is to be light in color, and to reflect rather than absorb the Sun's rays.

dark虽然没有说到，但这一句的比较含义还是存在。

虽然我定位在这里

就是不觉得和dark 在比

再理解理解

谢谢版版

按常识推断，应该是b

以下是引用quanner在2006-7-13 13:49:00的发言：

虽然我定位在这里

就是不觉得和dark 在比

再理解理解

谢谢版版

是和dark比的，因为颜色变浅可以反射阳光，而不是吸收阳光。

这意思就说，假如颜色不变浅，那就是会吸收多一些的阳光。颜色不变浅，也就是颜色深dark的意思，可以推出，颜色深，那就是会吸收更多的阳光。

that is 颜色浅比颜色深吸收的阳光少。It does not absorb sunlight as much as dark colors.

选b

HEHE

 谢谢