/ðeə(r); ðɛr/
possess det of or belonging to them 他们的; 她们的; 它们的
*Their parties are always fun. 他们的聚会总是很有趣.
* Their own car is being mended this one is hired. 他们自己的汽车正在修理--这辆是租的.
* Their fame rests entirely on one record. 他们完全是靠着一张唱片出的名.

determiner [possessive form of 'they']
[Date: 1100-1200; Language: Old Norse;Origin: theirra 'theirs']
belonging to or connected with people or things that have already been mentioned
　They washed their faces and went to bed.
　The twins spend all their time together.
　People had moved back into their own homes.
used when talking about someone who may be male or female, to avoid saying 'his or her'
　Everyone is free to express their own opinion.
　Each student will have their own course-work folder.
→his