他们的名词性物主代词用英语怎么说

Theirs had been a happy and satisfactory marriage.

他们的'婚姻曾经一直幸福美满。

Our children go to the same school as theirs.

我们的孩子和他们的孩子上同一所学校。

It's a favourite game of theirs.

这是他们最喜爱的游戏。

It was a neighbourly gesture of theirs.

这是他们友好的表示。

There was a big group of a dozen people at the table next to theirs

他们旁边的桌上坐了一大群人，有十几个。