they的三种形式
Their是形容词性物主代词，theirs是名词性物主代词，them是宾格，themselves是反⾝代词。they是第三⼈称的复数形式，⽆性别之分，代表已提到过的⼀些⼈或事，在句中多⽤作主语，通常放在它所指代的名词之后，偶尔也可放在它所指代的词之前。
They are going to move to a new house next week.下星期他们将迁⼊新居。
I have a dog and a cat， but they fight all the time.我养了⼀只猫和⼀只狗，但它们⽼是打架。
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。They found a labyrinth of tunnels under the ground.他们发现了⼀处迷宫似的地道。
