单数1. They shouldn't treattheir motherin this disrespectful way.他们不能这样无礼地对待亲生母亲。

语境中只有一位母亲

2. The children cried when they couldn't get into the house;their motherhad barred them out.孩子们进不了屋，又哭又叫，他们的妈妈把他们关在了门外。不只是一个“妈妈”或意思是“妈妈们”的时候，mother是复数，后面加s，用Their mothers例句：

1. Many daughters assume thattheir mothersare invulnerable.很多女儿都认为她们的母亲无比坚强。

2. Children cannot do withouttheir mothers.小孩子不能离开妈妈。