These are their books.Can you give them to them?
their他们的,是物主代词,后面要接一个名词；第一个them指books；第二个them指双方都知道的人.由于第二空和第三空都是作宾语,所以用了宾格them.
不明白的再问哟!请记得采纳,多谢!