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Extinction is a process that can depend on a variety of ecological, geographical, and physiological variables.These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions.However, the fossil record shows that extinction occurs in a surprisingly definite pattern, with many species vanishing at the same time.

Which of the following, if true, forms the best basis for at least a partial explanation of the patterned extinctions revealed by the fossil record?

正确答案: A

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大全-7-9,大全-7-16

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楼主
发表于 2004-11-1 23:28:00 | 只看该作者

大全-7-9,大全-7-16

  

9.     Extinction is a process that can depend on a variety of ecological, geographical, and physiological variables. These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions. However, the fossil record shows that extinction occurs in a surprisingly definite pattern, with many species vanishing at the same time.


Which of the following, if true, forms the best basis for at least a partial explanation of the patterned extinctions revealed by the fossil record?


(A) Major episodes of extinction can result from widespread environmental disturbances that affect numerous different species.


(B) Certain extinction episodes selectively affect organisms with particular sets of characteristics unique to their species.


(C) Some species become extinct because of accumulated gradual changes in their local environments.


(D) In geologically recent times, for which there is no fossil record, human intervention has changed the pattern of extinctions.


(E) Species that are widely dispersed are the least likely to become extinct.


答案是A,不明白为什么A是前提




16.   The imposition of quotas limiting imported steel will not help the big American steel mills. In fact, the quotas will help “mini-mills” flourish in the United States. Those small domestic mills will take more business from the big American steel mills than would have been taken by the foreign steel mills in the absence of quotas.


Which of the following, if true, would cast the most serious doubt on the claim made in the last sentence above?


(A) Quality rather than price is a major factor in determining the type of steel to be used for a particular application.


(B) Foreign steel mills have long produced grades of steel comparable in quality to the steel produced by the big American mills.


(C) American quotas on imported goods have often induced other countries to impose similar quotas on American goods.


(D) Domestic “mini-mills” consistently produce better grades of steel than do the big American mills.


(E) Domestic “mini-mills” produce low-volume, specialized types of steels that are not produced by the big American steel mills.


答案是E,Those small domestic mills will take more business from the big American steel mills than would have been taken by the foreign steel mills in the absence of quotas.为什么会发生这种情况,E为什么是削弱?



THANKS IN ADVANCE


沙发
发表于 2004-11-1 23:40:00 | 只看该作者

9。这是解释题。解释奇怪现象。

物种的灭绝模式是random。但化石记录却显示很多物种同时消失,模式固定。A说大规模的影响多数物种的环境变迁导致物种灭绝的主要事件。从而解释了多数物种同时灭绝的原因。又和物种的灭绝模式是RANDOM的没矛盾

板凳
发表于 2004-11-2 03:24:00 | 只看该作者

希望一次只一个贴

16。关键理解原文最后一句话:小MILLS将比没有进口限制时的外国公司从大MILLS抢的生意多。即如果限制了进口,这块生意给小MILLS抢去了,而且还要再从大MILLS抢一块。E的意思为大小MILLS公司的生意不同。不存在抢生意问题。故WEAKEN原文最后一句话。所以将最后一句话改为:Domestic “mini-mills” produce low-volume, specialized types of steels that are not imported。一样是答案。

地板
 楼主| 发表于 2004-11-2 08:06:00 | 只看该作者

哦,明白了

谢谢LAYWER-1的解答

不好意思,我下回会注意一次只贴一个的

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