帮忙解释一下这个！

Q14:

Guidebook writer:  I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward.  Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.

Which of the following, if true, most seriously weakens the guidebook writer’s argument?

1. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
2. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
3. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
4. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
5. The average length of apprenticeship for carpenters has declined significantly since 1930.

Answer：d

呵呵，顶顶！哪位nn给解答一下啊

菜鸟飞过~~

文中的focus在于1930年以前为hotels干活的木匠和1930年以后为hotels干活的木匠对比

A 1930前为hotels干活的木工活和1930年以前不为hotels的木工活对比 是无关比较

B 无关

C 之前和之后可用材料其实是无关的 即使不用无关排除 在使用相同材料的情况下所做出的木工活质量是不同的 更加说明是木匠自身skill的问题 这个选项反而排除了一个可以削弱的他因

D 文中得出以前优于现在的基础是现有的建筑的对比 而这个选项说的是1930年前质优的建筑才会留存到现在 也就是说并不是1930年前的建筑都是现存的这个水平 质量不好的早已不存在了 直接反对了1930年前现有建筑和1930年后的建筑都可以代表一段时期的整体水平进行比较

E 加强