把下列句子改成祈使句
1、Your friend lost her purse.She looked unhappy.You don't want her to worry.
2、Miss Yan asks the students to look at the blackboard.
3、You say politeiy to let the others make little noise.
4、It is so cold in room. Your mother asks you to close the door.
5、You are ill,the doctor advises you to have a good rest.
6、The policeman tells the boys not to play in the street.