将下列句子改成定语从句
1.Hangzhou is a famous city in china .many people come to buy tea in that city.
2.She got so angry.I don’tknow the reason.
3.The old man saw some Germans taking apart the Amber Room and removing it.You are talking to an old man.
4.Xi’an is one of the few cities with city walls.Its walls remain as good as before.