2. 外语
  3. Polar bears are suffering in a 【C1】______(warm)world than ever before. Polar bears live in environments too cold for most ani

Polar bears are suffering in a 【C1】______(warm)world than ever before. Polar bears live in environments too cold for most ani

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问题    Polar bears are suffering in a 【C1】______(warm)world than ever before.
   Polar bears live in environments too cold for most animals. During much of the year, 【C2】______live and hunt on the frozen Arctic sea ice. Nature has prepared them for the cold conditions. But nothing has prepared the bears for the danger threatening the only home they know.
   The polar bears ’ world is【C3】m______.. Studies show that the polar ice 【C4】______(reduce)by 9. 8% every 10 years since 1978. Now about 20, 000 to 25, 000 polar bears live in the Arctic. Polar bears【C5】d______on the sea ice for their survival. "The sea ice is more than just this platform that the bears walk over. " says Andrew Durocher, a scientist 【C6】______ studies North American polar bear populations. " 【C7】______it, they can’ t exist. "
   Some melting and refreezing of the polar ice is natural. 【C8】______, in a warmer world, these cycles speed up, and bears have less time 【C9】______(hunt). Normally, they have three months in the spring when they gain more weight. The extra fat is used later, 【C10】______the bears are not actively hunting.
【C4】
选项
答案has reduced
解析 从该句话的since 1978可以得知，本题考查现在完成时的用法，故答案是has reduced。
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本试题收录于： D类竞赛（专科）题库大学生英语竞赛（NECCS）分类
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