托福Toefl作文模拟题附范文 第52篇:草率的判断是否可信

The reading passage was talking about the cause of extinction of Steller's sea cow, and showed three theories about it, such as overhunting, ecological changes and fur traders from Europe. However, the professor pointed out the several shortages of those theories. First off, hunting by native people might be the cause of extinction. The man stressed that the feature of sea cow, which had 9 meters long and weighed nearly 10 tons, mean that food-cosuming was likely to spend over months for native people to finish one of them. According to the small population of native people and large crowds of sea cows, it was impossible for native people to overhunt widespread sea cow in such great degree. Bonus, the declination of Kelp which was inclined to be main food source for sea cow causing by the ecological changes, leading to diminish the numbers of sea cow as food-shortage. Nevertheless, even if there had happened any ecological changes, the board influence certainly appeared to other marine animals. Unfortunately, the numebers of other marine animals such as whale were not declined by the evidences. Additionally, someone figured out that fur traders might be the reason of the phonomenon. While the evidence clear out that the numbers of sea cows had already kept in a small condition before the European coming. To come up with the seriously problem which caused the declination should need any other theory expect current one.