我认为feifei Lsat逻辑精选题No.64里答案有误！！

If the city council institutes new parking regulations, city revenues will surely increase, since studies have conclusively shown that, if such parking regulations are put into effect, there is an increase in parking violations, and an increase in parking violations will result in a greater number of parking fines collected.

64. If the statements in the passage are true, which one of the following must also be true?

A.        Unless there is an increase in the number of parking violations in the city, city revenues will not increase.

B.        If the city council institutes new parking regulations, the council will fall from favor with the citizens.

C.        The city council will institute new parking regulations only if an increase in city revenues can be expected to result.

D.       If the city council’s new regulations cause more parking violators to be ticketed, the city revenues will increase.

E.        Unless the city institutes a complex system of parking regulations, the city cannot expect traffic violations to increase.

原版分析：

Choice C just repeats the conclusion: institution of new regulations -> increase of city revenues. it fails to fill the gap between institution of regulations and increase of revenues.

new regulations -> more violations-> more fines collected(increase of revenues)

D is correct.

我得分析：

题目实际上是个演绎推理，从文中只能推断C是对的，因为C基本就是重复了文中的结论。D只是一个必要条件，提供某种支持而已，怎么可能断定就是通过多开Ticket就赚钱了，也许新制定的法规是押送违章者去强迫为政府劳动打工呢！

至少从题目的问法来看，C是完全没有问题的，即便它只是把文中的结论重复一遍，但是logically absolutely correct!

请大侠们指正！

个人认为，你的思路不是很正确。

从C可以推出：The city council will institute new parking regulations 推出   an increase in city revenues can be expected to result.

即：an increase in city revenues can be expected to result. 是The city council will institute new parking regulations的必要条件。

这从原文无论如何是推不出的。

你再仔细想想。

我觉得这不用推理，因为文中已经给出了。。

文中第一句话：If the city council institutes new parking regulations, city revenues will surely increase。

only if 是必要条件；if是充分条件。

原文是：the city council institutes new parking regulations 推出  city revenues will surely increase

而答案C是The city council will institute new parking regulations 推出   an increase in city revenues can be expected to result.

不知道是否是你没看清楚还是怎么？？？

if a, b  是a 推出b. 所以原文是：the city council institutes new parking regulations 推出  city revenues will surely increase

a only if b 还是a 推出b, 所以The city council will institute new parking regulations only if an increase in city revenues can be expected to result 还是推出原文结论。

你应该看仔细些才对。

应该是我看错了。

不过，你对答案的怀疑仍然没有道理。

原文是If the city council institutes new parking regulations, city revenues will surely increase

而The city council will institute new parking regulations only if an increase in city revenues can be expected to result.

不是一个概念。

所以，C必然不对。

D is correct.

The first sentence is a claim that depends on the studies. The reasoning is "more fine collected" --> "increase revenue". So D confirm one assumption "an increase in parking violations will result in a greater number of parking fines collected".