231 In the 1980's the rate of increase of the minority population of the United Stated was nearly (twice as fase as the 1970's) b:twice as fast as it was in c: twice what it was in 选c, b为什么不对？
236 Unlike other arachnids, which have their nerve cells evenly distributed along their (bodies,the scorpion's nerve cells are clustered in its head, like a mammal's.) c:body,the scorpion has a cluster of nerve cells in its head, as a mamal does. 选c，可是为什么用their body 而不是their bodies?
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发表于 2003-8-6 09:30:00
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