they的形容词性物主代词是their；

their是复数第三人称的所有格形式,是复数形容词性物主代词,在句中只可用作定语,其后常接复数名词；

they

pron.他们;她们;它们;用以代替he或she，指性别不详的人;(泛指)人们，人人，众人

扩展资料

They're researching into ways of improving people's diet.

他们在研究如何改进人们饮食。

They'll respect you as long as you play fair.

只要为人正直，别人就会尊敬你。

They are campaigning to save the area from building development.

他们正开展一场反对在这个地区进行房地产开发的运动。

They agglomerated many small pieces of research into a single large study.