2022下半年英语六级听力常考时文:Marine Mammals

2022-11-29 08:28:00来源:网络

  新东方在线英语六级频道为大家整理了2022下半年英语六级听力常考时文:Marine Mammals,备考六级的同学可以收藏,预祝大家高分通过大学英语六级考试

  2022下半年英语六级听力常考时文:Marine Mammals

  1.Why does the autnor think some mammals should have returned to the sea? Because there is ... in the sea.

  2.What do humans want to get from marine mammals? Fur, ... and ...

  3.Which mammals in the sea have almost been wiped out by humans? Those ... mammals.

  Since there is such an abundance of food in the sea, it is understandable that some of the efficient, highly adaptable, warm-blooded mammals that evolved on land should have returned to the sea. Those that did have flourished. Within about 50 million years -- no time at all, geologically speaking -- one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in on these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on the top of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea. There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.

  以上就是为大家整理的“2022下半年英语六级听力常考时文:Marine Mammals”内容供大家学习,希望能够对大家有所帮助。


英语四六级无忧计划立减1000元

-->

扫码即刻查分 四六级最新答案

四六级好课 海量资料定期更新

更多资料
更多>>
更多内容
更多>>
更多公开课>>
更多>>
更多资料