They were unaccustomed to such military setbacks...是什么意思？

They were unaccustomed to such military setbacks...

他们还不习惯这样的军事挫败。

they

pron. 他/她/它们，人们，大家，政府，当局，她们；

例句
The storms had abated by the time they rounded Cape Horn.
他们绕过合恩角时，暴风雨已经减弱。

were

be的过去时复数和第二人称单数形式，有时代替 was,用于条件从句、动词 wish 之后等；

例句
Shops, houses, and vehicles were set ablaze.
店铺、房子和车辆全都陷于火海。

unaccustomed

adj. 不习惯的，不寻常的，奇怪的，不熟悉的；

例句
The point is that people grew unaccustomed to thinking and acting in a responsible and independent way. Herein lies another big problem.
关键是人们已不再习惯以一种负责任的、独立的方式去思考和行动。这其中就存在另一个大问题。

to

prep. 向，朝着，到，关于，属于；adv. 朝一个方向的，到某种状态，关闭；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

such

det. 这样的，那样的，如此，这样；

例句
...abstract principles such as justice...
正义等抽象原则

military

adj. 军事的，军用的，讨厌的，好战的；n. 军人，军队，武装力量；

例句
...a formal statement abjuring military action.
表示放弃军事行动的正式声明

setbacks

周折；

例句
Various setbacks and problems delayed production...
各种各样的挫折和问题耽搁了生产进度。