The machine is so advanced that it will start ______ you press the button.
If ___________, I will go to her birthday party.
I heard my sister ________ an English song when I passed by her room last night.
--What did our teacher say at yesterday’s meeting?--So you _______ to him carefully then.
Some teenagers like eating in fast food restaurant, ______ you can see everywhere in our city.
--May I park here?-- No, you _____. It is an emergency exist.