Simone1、词性上的区别
their是弊历形容词物主代词，后面胡渣可以接名词。
theirs是名词性物主代词，后面不能接名词
2、意思上的区别
their：他（她，它）们的
theirs：他们的; 他的或她的。
造句：
①、their
It would cost about £ 3,000 to install a new heating system in a flat such as theirs
在他们那样的一套公寓房里安装一套新的供暖系统可能要花费3,000英镑左右。
Theirs had been a happy and satisfactory marriage.
他们的婚姻曾经一直幸福美满。
②、theirs
There was a 裤卜悄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。
This child is nobody's child until someone makes her theirs officially.
在有人办理正式手续认领以前，这个孩子不属于任何人。
同义词解析：
they
pron.她们；他/她/它们；人们，大家;政府，当局。
例句：
They say there's plenty of opportunities out there, you just have to look carefully and you'll find them
他们说，那里机会多的是，你只要仔细找就能发现。
People matter because of what they are, not what they have
人之所以重要，不在于他们拥有什么，而在于他们是什么样的人。
The young horses broke in a pack, and over the first furlong, they remained in a pack.
几匹小马一起冲出，跑完头一弗隆后还没拉开距离。
