将下面每组句子改写成含有定语从句的复合句
1 he lost the book.I bought it for him
2 the play is very interesting we saw
3 my favorite city is harbin it is in the northest of china
4 tibet is the most fantastic place. I have ever visited it
5 I know the boy. his name is jack
6 he was an explorer .the chinese people are proud of
改成由who whose that which it而领导的定语从句