Some people associate migration mainly with birds. Birds do travel vast distances, but mammals also migrate. An example is the c

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问题     Some people associate migration mainly with birds. Birds do travel vast distances, but mammals also migrate. An example is the caribou, reindeer that graze on the grassy slopes of northern Canada. When the weather turns cold, they travel south until spring. Their tracks are so well-worn that they are clearly visible from the air. Another migrating mammal is the Alaska fur seal. These seals breed only in the Pribilot Islands in the Bering Sea. The young are born in June and by September are strong enough to go with their mothers on a journey of over 3, 000 miles. Together they swim down the Pacific Coast of North America. The females and young travel as far as southern California. The males do not journey so far. They swim only to the Gulf of Alaska. In the spring, males and females all return to the islands, and there the cycle begins again. Whales are among the greatest migrators of all. The humpback and blue whales migrate thousands of miles each year from the polar seas to the tropics. Whales eat huge quantities of plankton. These are most abundant in cold polar waters. In winter, the whales move to warm waters to breed and give birth to their young.
From the passage we can learn that______.

选项 A、people migrate like animals
B、only birds migrate
C、the female fur seals migrate only to the Gulf of Alaska
D、not all mammals migrate

答案D

解析 推断题型。从文章前几句得知:一些人认为有迁徙习性的主要是鸟类……但哺乳动物也“迁徙”;其中一个例子是……。另一个迁徙的例子是……。由此推断出并不是所有的哺乳动物都迁徙;因此选项D是答案。本题也可用排除法做:选项A、B、C均是错误的,所以只有D是正确选项。
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