They were expected to behave themselves.是什么意思？

They were expected to behave themselves.

他们应该守规矩。

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。

expected

adj. （用作定语）预期要发生的，期待中的；v. 期望( expect的过去式和过去分词 )，预料，要求，认为（某事）会发生；

例句
I never expected to feel so alive in my life again.
我怎么也没想到自己会再一次这样活力焕发。

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。

behave

vi. 表现，举止端正，自然反应；vt. 使守规矩；

例句
I'll behave toward them as I would like to be treated...
我会以希望别人对待我的方式来对待他们。

themselves

pron. 他[她，它]们自己，他们亲自，“himself”的复数，“herself”的复数；

例句
Most officers and men acquitted themselves well throughout the action.
大多数军官及士兵在整个战斗中表现出色。