2017年托福考试精选作文(3)
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菊石是因为小行星撞击后的一系列影响而灭绝的
一种叫ammonite的已灭绝生物，大致的原因是陨石撞击
阅读给出的三种观点：
陨石撞击导致这种生物暴露在酸雨之下，导致young ammonite be killed off后代也死亡
zooplankton作为ammonite的主要食物来源，陨石撞击导致海洋温度骤降，这种植物大量减少，导致ammonite因为缺少食物而灭绝
ammonite因为缺少氧气而无法在海洋里生存
听力逐一反驳：
举frogs的例子，同样是生活在水里，却没有被酸雨影响导致灭绝，所以ammonite的灭绝无法被证实是酸雨导致的
ammonite有许多groups，并不是所有种类的ammonite都以zooplankton为食
有一种种类的ammonite拥有在氧气不足的环境中也能生存下来的器官
最新托福综合写作范文：
The reading and listening both talk about whether the Ammonites died out due to asteroid apocalypse. However, the lecturer lists three reason to contradict what the passage indicates.
First, according to the lecturer, if the acid rains had killed off the ammonites on the surface of the water, another kind of frog, which also lived near the ocean, would become extinct as well. However, they still exist till now. Thus, the acid rain caused by asteroid impact mentioned in the reading passage was not the main reason.
Secondly, the reading passage indicates that the disappearance of zooplankton, which was the main food of ammonites, directly cause the extinction of them. However, zooplankton was just a small part of their food supply, according to professor, only a part of ammonites lived on zooplankton. Therefore, zooplankton didn’t account for that.
As to the third reason of absence of oxygen, the professor claims that the special physical structure allowed ammonites to live with hypoxia, which means that the statement in the reading that the impact taking away oxygen from the atmosphere killed all of ammonites is not correct.(185words)
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