单选题 We can infer from Dr Myers and Dr. Worm's paper that ______.

A、 the stock of large predators in some old fisheries has reduced by 90%
B、 there are only half as many fisheries as there were 15 years ago
C、 the catch sizes in new fisheries are only 20% of the original amount
D、 the number of larger predators dropped faster in new fisheries than in the old

【正确答案】 A

【答案解析】[试题分析] 这是一个推理题，也可以说是细节题。 [详细解答] 这道题目关键是要理解原文第二段的最后一句：... the biomass of large predators(animals that kill and eat other animals)in a new fishery is reduced on average by 80% within 15 years of the start of exploitation．In some long-fished areas，it halved again since then．前一个句子讲大型食肉动物减少了80%，即剩下20%，后句讲现在在某些long fished地区，又减少了一半即10%，所以总共减少了90%。