The doctor recommended that you _________ swim after eating a large meal.[ ]

Studies show that people are more _____ to suffer from back problems if they always sit before computer screens for long hours.

It was reported that a tall man with a black mask broke into the house and stole $5000_______.[ ]

15. — Who are the teenagers gathering at the school gate? — Well, if you _____ know, they are all my visiting students.

This is the ______ piano on which the musician created some of his greatest work.