Parents and teachers should help teenagers control their use of computer games ______be controlled by themselves.

_____ is no doubt _____ John’s knowledge of first aid saved Ms Slade’s life.

If you don’t study hard, you’ll regret, _____ you?

—I often see him working hard in his spare time. —________he has won the scholarship from time to time.

Rather than _____ on a crowded bus, he always perfers _____ a bike.