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标题: 请问这个E到底怎么解释了题目呢? [打印本页]

作者: frankzhiwei 时间: 2010-9-27 21:34
标题: 请问这个E到底怎么解释了题目呢?

In order to withstand tidal currents, juvenile horseshoe crabs frequently burrow in the sand. Such burrowing discourages barnacles from clinging to their shells. When fully grown, however, the crabs can readily withstand tidal currents without burrowing, and thus they acquire substantial populations of barnacles. Surprisingly, in areas where tidal currents are very weak, juvenile horseshoe crabs are found not to have significant barnacle populations, even though they seldom burrow.

Which of the following, if true, most helps to explain the surprising finding?

A.Tidal currents do not themselves dislodge barnacles from the shells of horseshoe crabs.

B.Barnacles most readily attach themselves to horseshoe crabs in areas where tidal currents are weakest.

C.The strength of the tidal currents in a given location varies widely over the course of a day.

D.A very large barnacle population can significantly decrease the ability of a horseshoe crab to find food.

E.Until they are fully grown, horseshoe crabs shed their shells and grow new ones several times a year.

求解释，谢谢！

作者: lsqandsam 时间: 2010-9-27 21:51
题目中的推理是：因为 crabs要withstand currents 所以他们在小时候要在沙子里挖洞。而又由于在沙子里挖洞导致了barnacles不往他们的shells上靠，因此只有到他们长大了，不挖洞了的时候，barnacles才会一直的靠在他们shells上。 surprising find是在一个没有current的地方，crabs身上也没有barnacles, 这个之所以surprising 就是因为根据上面的推理，没有current的话crab就不用在沙子挖洞，因此身上应该有barnacles。E选项正好根据题目的推理提供了一个理由，因为crab要换壳，把壳上的barnacles换掉了，这样surprising find就被解释了。

作者: shencangbulu 时间: 2010-9-27 21:53
没查字典,用最直白的语言解释下.需要一点想象力的.
In order to withstand tidal currents, juvenile horseshoe crabs frequently burrow in the sand. Such burrowing discourages barnacles from clinging to their shells.
juvenile记得是青少年的意思.想象你在海边,一个大浪打过来的时候,力量很小的生物就会被冲到很远的地方去对吧,所以呢,为了不被冲走,某种小蟹就会把钳子埋到沙子里面,就象我们的手紧紧抱着树干不被龙卷风吹走一样.有所阻力.后面的意思是猜的,这个barnalce应该是小蟹身上的某种东东,本来呢,它是粘在蟹背上的,现在呢,因为大浪冲啊冲,小蟹就像洗过澡一样干净~
When fully grown, however, the crabs can readily withstand tidal currents without burrowing, and thus they acquire substantial populations of barnacles.
那长大之后呢,蟹的力量足够大到可以对抗潮汐大浪的冲击了,这样它们背上的那种东东应该就会多起来了.
Surprisingly, in areas where tidal currents are very weak, juvenile horseshoe crabs are found not to have significant barnacle populations, even though they seldom burrow.
但奇怪的是,人们发现在大浪不多的地方,小蟹们背上某种东东数量也不多,求原因.E说的类似于金蝉脱壳吧,它生长的自然规律是要每年类似于像脱皮一样换掉一层吧,所以也不可能积得很多

作者: 21Guns 时间: 2013-10-6 12:23
E说，并不是burrow sand这个动作使得young crab得以幸免长barnacle，而是因为他们会换壳，就算长了barnacles也因为换壳够勤快，所以看不到身上有之。而成年的crab不换壳（这没有人不同意吧！），所以身上的crab除不掉，人们就以为成年的crab会长barnacles了。

因此这个“burrow sand”的动作的发生群体和“换壳”的动作的发生群体刚好是一样的，即young crab。而前者作为解释在海浪弱的地方失效了（海浪弱则不burrow，不burrow则长barnacles，而事实并非如此），后者则能够解释为什么没海浪young crab也不长barnacles，因为这跟“海浪-burrow”没有联系（有联系则事实不可能是这么surprising）。

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