pron. 他（她，它）们的,在提及性别不详的人时，用以代替 him 或 her
their可以用作代词
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。有时为了避免显示性别, their还可代替his, her用作anybody, anyone, everyone等词的物主代词,此时其后可接单数名词。有时their还可用作动名词的逻辑主语。
their还可与own连用构成强调。
1、They have maintained their optimism in the face of desolating subjugation.
面对遭征服的悲惨命运，他们保持了乐观的态度。
2、He said they should turn their fire on the Conservative Party instead.
他说他们应该掉转枪口，向保守党开火。
3、Husband and wife are now taxed separately on their incomes.
现在夫妻双方分别按各自的收入纳税。