用合适的特殊疑问词（组）填空,补全对话
1.
——_____ does your sister do?
——she is a nurse.
2.
——_____ do you go to school every day?
——on foot.
3.
——_____ is your mother angry with you?
——because i failed the exam.
4.
——_____ students are there in your class?
——forty.
5.
——_____ is christmas day?
——on december 25.