argument 84
Two studies of amphibians in Xanadu National Park confirm a significant decline in the numbers of amphibians. In 1975 there were seven species of amphibians in the park, and there were abundant numbers of each species. However, in 2002 only four species of amphibians were observed in the park, and the numbers of each species were drastically reduced. One proposed explanation is that the decline was caused by the introduction of trout into the park's waters, which began in 1975. (Trout are known to eat amphibian eggs.)"这道题虽然是老题，但是他把一部分删了，我拼死拼活只能找出两个错误！！
1.只看到不代表就存在那么多。
2.不一定是trout导致了amphibian的减少。
那个G友还能帮我找个啊！！谢谢啦
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