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  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

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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 author’s main purpose for writing this was to______.
选项 A、inform
B、entertain
C、warn
D、persuade
答案A
解析 纵观全文，作者主要讲述了白垩纪时期的生物、植物以及大陆板块的变化。据此可知，作者是要告知读者某些信息，因此A项正确。
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