171.
A recent report determined that although only three percent of drivers on Maryland highways equipped their vehicles with radar detectors, thirty-three percent of all vehicles ticketed for exceeding the speed limit were equipped with them. Clearly, drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly than are drivers who do not.
The conclusion drawn above depends on which of the following assumptions?
(A) Drivers who equip their vehicles with radar detectors are less likely to be ticketed for exceeding the speed limit than are drivers who do not.
(B) Drivers who are ticketed for exceeding the speed limit are more likely to exceed the speed limit regularly than are drivers who are not ticketed.
(C) The number of vehicles that were ticketed for exceeding the speed limit was greater than the number of vehicles that were equipped with radar detectors.
(D) Many of the vehicles that were ticketed for exceeding the speed limit were ticketed more than once in the time period covered by the report.
(E) Drivers on Maryland highways exceeded the speed limit more often than did drivers on other state highways not covered in the report.
171.
The conclusion concerns regularly exceeding the speed limit, but the data derive from isolated occasions when drivers exceed the speed limit and are ticketed. The conclusion thus assumes that these instances provide evidence of regular behavior-that drivers ticketed for exceeding the speed limit are likely to be drivers who regularly exceed it. Choice B states this assumption and is the best answer.
这道题为什么选B，我觉得原文由两个论据推导出结论，这两个论据跟本是无关的啊，和结论有什么关系呢？搞不懂啊 | 
