pron. 他们的
1. This book is theirs, not mine.
这本书是他们的，不是我的。
2. The children played with their toys, but the dog took theirs.
孩子们在玩他们的玩具，但狗狗拿走了他们的。
3. I thought the ideas were ours, but they actually belong to them and theirs.
我以为这些想法是我们的，但实际上它们属于他们和他们的。