A survey of the opinions of experts that three hours of outdoor exercise a week good for one’s health.
David is such a good boy _______ all the teachers like.
The thief tried to break away from the policeman who ______ him, but failed.
The factory was built in a secret place, around ______ high mountains.
The telephone _______ three times in the last hour, and each time it ________ for my father.
The ______ has become extremely tense. A war could break out any time between the two sides.