_______ entering the classroom, remember to take your seat and turn off your cell phone.
I strongly recommended that more phrases ____ use of in his composition.
____ again and again, the sayings have been learned by heart so far.
He was on the point of setting off for Shanghai ____ his girl friend called him.
My friend asked me to play ____ volleyball, but I’m tired and I don’t think I’ve got ____ energy.
The patient in hospital is ready to accept ____ help she can get.