【解决】阅读240一道逻辑-assumption的疑惑，大佬们帮帮忙！！！

ba1a糖儿UID：3918923

Benovians set their clocks back an hour for the winter. The result is that, during winter’s
short days, it is light when most commuters drive to work, but dark when they drive back
home. Darkness contributes to accidents. Changing the clocks, however, does not actually
increase the amount of driving done in the dark, so it is unlikely to have any effect on
Benovia’s automobile accident rate.


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

A. The average number of hours that Benovians drive when it is dark is greater for days during
the winter than for days during other times of the year.
B. In Benovia, hazards to safe driving that are made worse by darkness are as likely to occur
in the morning as in the evening.
C. The majority of cars on Benovia’s roads during a given day are those of people commuting
to or from work.
D. The majority of automobile accidents in Benovia take place when it is dark.
E. Driving conditions are no worse in Benovia in the winter than during the rest of the year.

KEY:  B   
看到之前有版友发帖提问，看过解析之后还是很有疑问！！

我的问题：
题目说Dark→accident（Darkness contributes to accidents.）

key：白天黑夜的accident rate一样

黑夜导致accident，所以白天也一样，不会一起增加吗？为啥可以支持结论说unlikely to have any effect on
Benovia’s automobile accident rate？  为啥不是一加一减，这样才不影响才对啊？


有大佬帮帮忙吗！！！！！！！！感激！！！

ba1a糖儿UID：3918923

settled！！

是我自己理解错误！

In Benovia, hazards to safe driving that are made worse by darkness are as likely to occur
in the morning as in the evening.
accident rate如何和之前没有不同？  这里的dark→accident，是大前提，结论在说时间变，事故率不变
调整前后开车的accident rate都不变！！所以回家时天黑的事故率=上班时天黑的事故率，因为题目限定的范围只是dark→accident，白天的情况不用考虑

天黑事故率=a晚上回家/b早上上班黑天  自变量不变，所以因变量可以不变

不知道这样理解对不对T T 逻辑越来越迷糊了

ba1a糖儿UID：3918923

要使得结论成立，就应该缩小change前后的差异？
change—/→AR↑， 那么变化前后的情况要analogous就行

变化前起早黑，变化后走夜路黑   一样黑，一样的AR