用could,need,can't,may,must填空

问题描述:

用could,need,can't,may,must填空
1.Jane isn't in the school,I think she ________be ill.
2.The key ________ be Kangkang's,his is in the lock.
3.You________wash your hands before meals.
4.You _______to drink plenty of water.
5._________you help me?What should I do?I don't know.

1,MAY
2,CAN’T
3,MUST
4,NEED
5,COULD