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标题: GWD Q9, B or E ? [打印本页]

作者: debralee 时间: 2008-4-17 15:14
标题: GWD Q9, B or E ?

选B还是选E？答案是E, 我觉得B更合适啊。

Q9:

Manatees, aquatic mammals inhabiting Florida’s rivers and coastal waters, swim close to the surface and are frequently killed in collisions with boats. To address the problem, boat traffic in manatee-populated waters is being required to maintain very low speeds. Unfortunately, manatees are unable to hear low-pitched sounds and a boat’s sound lowers in pitch as the boat slows. Therefore, this approach may in fact make things worse rather than better.

Which of the following, if true, casts most doubt on the conclusion?

The areas where boats would have to maintain low speeds were decided partly on the basis of manatee-population estimates and partly from numbers of reported collisions between manatees and boats.
Because the water hyacinth that manatees feed on grows best in water that is nearly still, water hyacinth beds can be disturbed or damaged by fast-moving boat traffic.
Over the last several decades, boat traffic in Florida’s coastal waters has been increasing almost continuously and now represents the greatest threat to the endangered manatee population.
The sound of a boat engine generally travels much further under water than it does through the air.
When experimenters exposed manatees to the recorded sounds of boats moving at various speeds, the creatures were unable to discern the sounds over normal background noise.

作者: anistonlucky 时间: 2008-4-18 13:46

选E

E说了 manatees 他自己根本分不清各种speed的sound,这样就攻击了题目说的，是因为boat speed is low造成的，

比如，一个人是个聋子，你说我把音乐放小声了，才造成他听不见的，这不是鬼讲吗？

B肯定错，water hyacinth 无关啊！我一看water hyacinth ，就不用看后面的句子了啊！鬼讲！

作者: debralee 时间: 2008-4-18 15:48

多谢多谢！！

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