短句1. More investment is needed.

短句2. Passengers will not be willing to pay more (indefinitely) (无限期地).

短句3. They must also endure cramped (拥挤的), unreliable （不可靠的，不靠谱的） services. 这句话还可以缩短为 They must endure services.

短句4. The (cramped unreliable) services are punctuated (打断) (by regular chaos). 这句话还可以缩短为：The services are punctuated. (punctuate 近义词 disrupt) punctuated by regular (经常的；频繁的) chaos (混乱；骚乱）

短句5. Timetables (时刻表) are changed.

短句6. (Planned) maintenance (维护；维修) is managed (incompetently). 这句话还可以缩短为 Maintenance is managed.

咱们看看它是如何从短句子变来的吧！

“短句1 but 短句2” 构成句子的主干。

那在什么情况下乘客不愿意无限期地多付钱呢？加上if条件句，也就是if 短句3。More investment is needed, but passengers will not be willing to pay more indefinitely if they must also endure cramped, unreliable services. 作者觉得用cramped, unreliable两个词去吐槽这种服务的差还不够，所以有了过去分词短语 punctuated by regular chaos，这个短语表被动，由短句4变化而来。那什么时候会发生regular chaos呢？作者加了when引导的时间状语从句。这个时间状语从句由 when 短句5 短句6 构成。句首加上连贯文章中上一句的Yes, 就变成了考研真题中的原句。