7.听下面一段材料,回答18-20题. 18.Why does Mrs Lin want to move out of her flat? A.She wants to buy a new one. B.This flat is too small. C.The environment there is too terrible. 19.What does Mrs Lin often hear the boys doing? A.Singing all night. B.Talking and laughing loudly at night. C.Dancing to loud music all the time. 20.What stops Mrs Lin from sleeping well? A.Talking and laughing in the neighborhood. B.The light in the crowded street. C.The loud dance music from outside.