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?
The use of acoustic alarms increases the number of commercial fish caught by the fishing company's boats.
When disoriented, harbor porpoises are not significantly more likely to be killed by other boats.
Environmentalists advocate the use of acoustic alarms as a means of protecting the harbor porpoise population.
The alarms were installed at the time of year when harbor porpoises are most plentiful in the Massachusetts waters.
The cost of installing acoustic alarms on fishing boats is less than the cost of repairing nets damaged by harbor porpoises.
P:自从在船上安装acoustic alarms以后,被网抓住的porpoises数量从每个月8条降低到了每个月1条。-> C: acoustic alarms 正在拯救porpoises的生命
choice b, 当被打乱方向,porpoises不会慌乱中被其他船杀死。 correct,取非削弱结论
https://www.manhattanprep.com/gmat/forums/cr-to-prevent-harbor-porpoises-t32812.html
不能把are saving the lives理解为相关果因推理,把D理解为他因削弱
但是herl思路把很多类似题目理解为相关果因,选项为其中一个CQ。 如何区别? 如果有因果推理的选项则优先选