2. 外语
  3. The last of the dinosaurs lived during a time called the Cretaceous period. This time period lasted from about 135 million to 65

The last of the dinosaurs lived during a time called the Cretaceous period. This time period lasted from about 135 million to 65

admin2014-01-13  52
问题     The last of the dinosaurs lived during a time called the Cretaceous period. This time period lasted from about 135 million to 65.5 million years ago. Some sources give the years of 146,145, or 144 million to 65 million years ago.
    In the Cretaceous period, the middle of North America was covered by a shallow sea. The Atlantic Ocean began opening up between Europe and North America as those continents rifted. Other continents that had begun pulling away from each other in the Jurassic continued drifting apart. India was an island by itself.
    Evergreen trees, mosses, and ferns had been the main types of plants, but now in the Cretaceous, flowering plants appeared. Bees did, too. Hardwood trees like oaks and maples first appeared in the fossil record.
    Modem birds and mammals came into the fossil record. Tyrannosaurus and Triceratops came into existence. So did other ceratopsian dinosaurs, relatives of Triceratops, with their wide variety of facial horns and neck frills. Great herds of perhaps 10,000 Triceratops roamed the edges of the North American Inland Sea. The climate began to cool.
    At the end of the Cretaceous, another mass extinction wiped out as much as 90 percent of marine life and 50 percent of life on land. There were no more dinosaurs after the end of the Cretaceous, at about 65.5 million years ago. The Cenozoic era, also called the Age of Mammals, began.
The mass extinction at the end of the Cretaceous period______.
选项 A、killed all the dinosaurs
B、killed half of all life on land
C、killed as much as 90 percent of marine life
D、all of the above
答案D
解析 根据文中最后一段的“At the end of the Cretaceous，another mass extinction wipedout as much as 90 percent of marine life and 50 percent of life on land．There were no moredinosaurs after the end of the Cretaceous，at about 65．5 million years ago．”可知，在白垩纪末期，另一次大规模的灭绝摧毁了多达90％的海洋生物，50％的陆地生物。白垩纪末期后，恐龙都消失了。据此可知，A、B、C三项都与文意相符，因此D项正确。
转载请注明原文地址:https://kaotiyun.com/show/46QO777K
0

考博英语

相关试题推荐
随机试题
最新回复(0)