FeiFei-64求教

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.

求教：A为什么不行？是削弱吗？请指教！

我不觉得A是削弱，感觉上题目把more violaters will be ticketed做为city revenues will increase的充分条件。而A将其变成必要条件了。

可以参考这里的解释：http://forum.chasedream.com/dispbbs.asp?boardID=24&ID=62941&page=1