It is unknown whether we will go for an outing tomorrow.
It hasn't been decided yet who will be our monitor.
It is a question of great importance whom we must stuey for.
It is unknown what caused the accident.
It is right whatever you did.
It is unknown whose watch was lost.
不是所有的都能改成it is...that...
主语从句如果是个问句,那么连词就不能用that,只能用那个问句的疑问词.