To prevent harbor porpoises from getting tangled in its nets and suffocating, a fishing company installed acoustic alarms on all its boats that fish in waters off Massachusetts. The sound emitted temporarily disorients the porpoises and frightens them away. Since the installation of the alarms, the average number of porpoises caught in the company's nets has dropped from eight to one per month. The alarms, therefore, are saving the lives of harbor porpoises in those waters.
Which of the following is an assumption on which the argument depends?
29. (30663-!-item-!-188;#058&005676) To prevent harbor porpoises from getting tangled in its nets and suffocating, a fishing company installed acoustic alarms on all its boats that fish in waters off Massachusetts. The sound emitted temporarily disorients the porpoises and frightens them away. Since the installation of the alarms, the average number of porpoises caught in the company's nets has dropped from eight to one per month. The alarms, therefore, are saving the lives of harbor porpoises in those waters. Which of the following is an assumption on which the argument depends? (A) The use of acoustic alarms increases the number of commercial fish caught by the fishing company's boats. (B) When disoriented, harbor porpoises are not significantly more likely to be killed by other boats. (C) Environmentalists advocate the use of acoustic alarms as a means of protecting the harbor porpoise population. (D) The alarms were installed at the time of year when harbor porpoises are most plentiful in the Massachusetts waters. (E) The cost of installing acoustic alarms on fishing boats is less than the cost of repairing nets damaged by harbor porpoises. 答案是B。我也认同B。想知道D为什么不对。 如果这个数据是在porpoises很少的时候得到的,那很可能会从8减少到1,而不是因为alarms啊。
D:题干中说the average number of porpoises caught in the company's nets has dropped from eight to one per month,即每月抓到的平均数从8降到了1. D说在海豚最多的时候安装,那么数量从8降到了1正说明有效果。如果是在最少的时候安装,也说明有效果。楼主是不是这个意思:在最多的时候安装,后来海豚越来越少,因此补到的也变少了。其实这是有可能的。但是相对于B还是不够好。 另外我感觉假设就是根据前提来推理,D个人感觉不太像前提,呵呵~ 请NN指教
(B) When disoriented, harbor porpoises are not significantly more likely to be killed by other boats.(not 去掉--?当被迷惑了,海豚更容易被其他船只撞上,更死得快--?驳斥了文章:迷惑使得它们被吓走-从而保护了海豚)
(B) When disoriented, harbor porpoises are not significantly more likely to be killed by other boats.(not 去掉--?当被迷惑了,海豚更容易被其他船只撞上,更死得快--?驳斥了文章:迷惑使得它们被吓走-从而保护了海豚)
(B) When disoriented, harbor porpoises are not significantly more likely to be killed by other boats.(not 去掉--?当被迷惑了,海豚更容易被其他船只撞上,更死得快--?驳斥了文章:迷惑使得它们被吓走-从而保护了海豚)