is和does的区别是什么?如：when does your brother do his homework?可不可以说

is和does的区别是什么?如：when does your brother do his homework?可不可以说成 when is your brother
如：when does your brother do his homework?可不可以说成 when is your brother do his homework?如果可以,为什么?什么情况下不可以?如果不可以,为什么?什么情况下可以?我最多可以提高悬赏10分,只要讲明白即可