They are completely outworn and exhausted.

他们极度疲惫堪，筋疲力尽。

Every historian — sometimes unconsciously, but always inevitably — must have put to himself the question: How long could such-or-such an outworn system last?

每位历史学家——有自觉， 但总可避免——都必须向自己提出这样题：这样或那样的过系统能持续多久？

But even as they drew near the fences at last she closed her staring eyes, and would sleep; and they laid her down, and rested also, unheedfully, for they were utterly outworn.

可，即使他们快走近栅栏，她终于闭上了瞪着的眼睛，睡着了。他们就把她放下，也懒洋洋休息了，因为他们已经完全疲惫堪了。