用have to的适当形式或must填空

问题描述:

用have to的适当形式或must填空
1、Do you ___wash your clothes on sundays?
2、He ___stay at home and look after his brother today.
3、You ____finish your homework this afternoon.
4、They don't ____go there today.
5、____ she practise her guitar every day?
回答~

1 have to
2 must
3 must
4 have to
5 Must请问为什么(2)(3)用must?2 应该是has to 3 表示主观人为‘ 必须’