请用must和have to来代替下列带括号的部分.
she said (it would be necessary for us to)stay here.
(it is necessary for me to)have some help.
(it was be necessary for him to)go out last night.
对他来说昨晚出去是必要的
he must had go out last night
i must had have some help
she said we have to stay here
对么 不懂 一定要说明
并说明为什么