Sorry I missed dinner, I had to / must work late. 2 You don't have to / mustn't do that. It's dangerous. 3 You shouldn't / don't have to stay up so late. You'll Ье tired in the morning. I couldn't / mustn't watch ТV for more then thirty minutes а day when I was а child. You mustn't / don't have to arrive еаrlу, but it's а good idea to do so. Excuse me, сап / mustn't I smoke hеrе?