You_____go to bed at 9:30.That's our family rule
这里是用must还是have to
刚开始我认为是have to但是仔细考虑过后我认为是must
因为must表客观,而have to是主观,have to不得不,经常以我做主语.而这里是母亲说“你必须9点半睡觉”,That's our family rule,既然是家规,那么应该是客观了.