# 如何备考GMAT考试逻辑题型之一：逻辑跳跃

(1) Which of the following, if true, most seriously weakens the conclusion above?

(2) Which of the following, if true, most strengthens the argument above?

(3) Which of the following is an assumption on which the argument depends?

(4) Which of the following would it be most useful to establish in order to evaluate the argument?

GMAT逻辑题中会出现一些类似的推理：

For similar cars and drivers, automobile insurance for collision damage has always cost more in Greatport than in Fairmont.  Police studies, however, show that cars owned by Greatport residents are, on average, slightly less likely to be involved in a collision than cars in Fairmont.  Clearly, therefore, in-surance companies are making a greater profit on collision-damage insurance in Greatport than in Fairmont.

Which of the following is an assumption on which the argument depends?

Repairing typical collision damage does not cost more in Greatport than in Fairmont.

1. 先读问题，再读文章
2. 准确提炼前提和结论
3. 确定答案筛选方向，寻找选项

The violent crime rate (number of violent crimes per 1,000 residents) in Mead-owbrook is 60 percent higher now than it was four years ago.  The corre-sponding increase for Parkdale is only 10 percent.  These figures support the conclusion that residents of Meadowbrook are more likely to become victims of violent crime than are residents of Parkdale.

The argument above is flawed because it fails to take into account

(A) changes in the population density of both Parkdale and Meadowbrook over the past four years

(B) how the rate of population growth in Meadowbrook over the past four years compares to the corresponding rate for Parkdale

(C) the ratio of violent to nonviolent crimes committed during the past four years in Meadowbrook and Parkdale

(D) the violent crime rates in Meadowbrook and Parkdale four years ago

(E) how Meadowbrook's expenditures for crime prevention over the past four years compare to Parkdale's expenditures