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Toprevent harbor porpoises from getting tangled in its nets and suffocating, a fishingcompany installed acoustic alarms on all its boats that fish in waters offMassachusetts. The sound emittedtemporarily disorients the porpoises and frightens them away. Since the installation of the alarms, theaverage number of porpoises caught in the company's nets has dropped from eightto one per month. The alarms, therefore,are saving the lives of harbor porpoises in those waters. Which of thefollowing is an assumption on which the argument depends? (A) The use ofacoustic alarms increases the number of commercial fish caught by the fishingcompany's boats. (B) Whendisoriented, harbor porpoises are not significantly more likely to be killed byother boats. (C)Environmentalists advocate the use of acoustic alarms as a means of protectingthe harbor porpoise population. (D) The alarms wereinstalled at the time of year when harbor porpoises are most plentiful in theMassachusetts waters. (E) The cost ofinstalling acoustic alarms on fishing boats is less than the cost of repairingnets damaged by harbor porpoises.
这题D应该也是对的吧，如果这个月海豚出现的概率本来就小，那抓到低于平均数的海豚并不能代表他们保护了海豚啊？求大牛指教！
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发表于 2016-9-3 00:08:13
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