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 bom 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 本题考查推理判断。根据常识可知,A项不正确;根据第一段第二句“Birds dotravel vast distances,but mammals also migrate.”可知,B项错误;根据第一段第六、七句“Another migrating mammal is the Alaska fur seal.These seals breed only in the PribilotIslands in the Bering Sea.”可知,C项错误。故这三项均可排除。所以,答案是D。
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