How frequently _______, the works of Shakespeare always attract many people.
Carl wanted to play a joke on Bob but gave himself _____ by laughing.
The rapidly growing birth rate brings about a lot of environment problems, which the government is supposed to take _____.
The two dogs started to fight, so we tried to _____ them.
Japan has to employ an increasing number of overseas workers because there is no easy solution to its labor _____.
The thieves _____ him _____ in the park, took his wallet and escaped.