请教og-171，前人的帖中没有提到我想问的问题。

cora_jin

请教OG-171
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.

前人的帖中都在讨论为什么B对，这个我已经理解了，但是我觉得D不是和B意思一样么，为什么不选D阿？是不是讨论的人数范围的问题啊，请教NN~~~

bedroom

以下是引用cora_jin在2005-9-27 9:13:00的发言：

请教OG-171
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.

前人的帖中都在讨论为什么B对，这个我已经理解了，但是我觉得D不是和B意思一样么，为什么不选D阿？是不是讨论的人数范围的问题啊，请教NN~~~

Ｄ开头用的ｍａｎｙ　ｏｆ，不能表示一般情况，所以不能用来描述那个ｍａｎｙ所在的那一大类人的情况

randomyoyo

d kind of weaken

If d is true, then although 33% of vehicles ticketed for exceeding the limit of speed were those with radar detectors, total ticketed vehicles with detectors may account for less than 33%, in that case, the assertion in the passage turns out to be susceptible to critisism.

If d is not true, that is, all the vehicles that were ticketed were ticketed only once during the report period, then we can sufficiently come to the conclusion that radar dectors tend to make people more carless.