Do the boys and girls have the same favorite ______(subject)?

问题描述:

Do the boys and girls have the same favorite ______(subject)?
到底是填单数还是复数啊~
Mike is ill.He ____(must/has to)go to the hospital.
是填must还是has to,为什么

单复都可以. has to更好.has to 表示*,不得不. must表示主观认为的必须