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问了这么多题，都不知道写清楚题号的，惭愧~~~~ 以后一定改正 A distemper virus has caused two-thirds of the seal population in the North Sea to die since May 1988. The explanation for the deaths cannot rest here, however. There must be a reason the normally latent virus could prevail so suddenly: clearly the severe pollution of the North Sea waters must have weakened the immune system of the seals so that they could no longer withstand the virus. 11. Which one of the following, if true, most strongly supports the explanation given in the argument? (A) At various times during the last ten years, several species of shellfish and seabirds in the North Sea have experienced unprecedented steep drops in population. (B) By reducing pollution at its source, Northern Europe and Scandinavia have been taking the lead in preventing pollution from reaching the waters of the North Sea. (C) For many years, fish for human consumption have been taken from the waters of the North Sea. (D) There are two species of seal found throughout the North Sea area, the common seal and the gray seal. (E) The distemper caused by the virus was a disease that was new to the population of North Sea seals in May 1988, and so the seals’ immune systems were unprepared to counter it. 答案给的是A 这道题第一遍看下来，发现没答案。E应该是起削弱作用吧。答案A想想说服自己的唯一理由就是：另外两种生物的数量下降为severe pollution的存在提供了佐证，但还是有点儿牵强啊。但其他选项更没边儿。crusoe大牛快现身吧~~ | 
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发表于 2009-5-6 22:20:00
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