Frank: Remember you have to be home by 8pm.
Jim: Yes dad!
Frank: If you're late you're grounded for a week.
Jim: I know. I won't be late.
Frank: Just want to make sure that we're absolutely clear on that.
Jim: If the bus is late it is not my fault though.
Frank: No excuses! Home by 7pm firm!
Jim has to be home by 8pm. Otherwise, he will be grounded for a week.