The professor ________at 8 o’clock,but he has not shown up yet,which worries all of us.
—You have just 15 minutes to get to the airport. —All right, I guess I can ________.
Let’s make good use of our energy and_________ wasting water, electricity, paper and so on.
He needs to improve his skills if he __________ the gold medal at the 2016 Olympics.
The teacher warned ________ was caught ________ during the test would be punished.
If he ________ quietly as the doctor instructed, Ronald would not suffer so much now.