填空题

Although the Arctic looks lifeless, there are animals moving about. Caribou travel up and down feeding on the grass beneath the snow. The polar bears have a thick, waterproof coat. They eat birds’eggs, berries and dead whales. Walruses get shellfish from the ocean with their tusks. Seals have a layer of fat to keep them warm. They like to eat fish.
The main idea of the paragraph is that although the (46) looks lifeless, there are a number of (47) there.
Walruses get (48) from the ocean with their (49) .
Seals have a (50) of fat to keep them warm.