Passage 4
At CapeChurchill in northeastern Manitoba, where the shore of Hudson Bay makes an abrupt 92-degree turn to the west, polar bears congregate in the autumn, waiting for the ice that is their home. By November, pack ice has formed beyond the fast ice, and the bears are moving. To be at the very tip of the Cape in November is to be in the middle of a slow but steadily flowing river of bears, methodically picking their way across the jumbled ice in a straight-line push for their hunting grounds.
The polar bears of Hudson Bay are a distinct population thriving at the southern end of their range. Polar bears live on seals, and to hunt them the bears must have ice to get to where the seals are. Yet in Hudson Bay the ice melts by July and the bears have to come ashore, there to spend four months eating very little, digging into sand dunes and dirt so they can stay cool in the summer “hear,” relaxing into a physiological state like that of black bears in winter dens. They are the polar bear population most accessible to humans, and they are not only the best studied but the most easily experienced by amateur naturalists, photographers, and just plain tourists. 213
16. With what aspect of bears lives is the passage mainly concerned?
A. Their evolutionB. Their hunting skills
C. Their temperamentD. Their seasonal movements
17. According to the passage, polar bears congregate at CapeChurchill during the
A. springB. summerC. fallD. winter
18. The author uses the expression “steadily flowing river of bears” (line7) to illustrate the
A. large number of migrating bears
B. bears graceful movements
C. danger the bears represent
D. bears´ love of the water
19. When the bears move out onto the ice, they look for their
A. densB. youngC. foodD. mates
20. It can be inferred from the passage that the polar bear population of Hudson Bay
A. is one of several polar bear populations
B. is unfriendly toward humans
C. consumes food voraciously during the whole yeas
D. is an endangered species
16.【答案】D
【解析】Their seasonal movements；本文没有涉及北极熊的进化A与性格C；对于它的捕猎海豹B，仅有一句话涉及，并非主要内容。本文第一段和第二段的大部分，谈的都是北极熊随季节变化而进行的迁移D。
17.【答案】C
【解析】fall；文中第一句中的主句指出北极熊在秋天聚集，正确答案为C。（北京安通学校提供）
18.【答案】A
【解析】large number of migrating bears；“steadily flowing river of bears”是一种形象的说法。把北极熊的行列比喻为一条“不停地流动的河流”，以说明其数目之多，正确答案为A。
19.【答案】C
【解析】food；第二段第二句后半句解释了北极熊走到冰上的原因：去到有海豹的地方捕捉海豹，而海豹是其藉以生存的食物，因而正确答案为C。
20.【答案】A
【解析】is one of several polar bear populations；本文最后一句是通过推论求解本题的主要依据。这一句中的主语They显然是指the polar bear population of Hudson Bay. 它们既然是“人最易接近的北极熊”，除了它们之外，必然还有人不那么容易接近的北极熊。由此可以推论：它们仅是北极熊中的一种而已，故正确答案为A。
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