Passage 3
Questions 17 to 20 are based on the passage you have just heard.

About how many different languages are there in the world（）

A．Drug use among American teens is increasing dramatically despite years of antidrug campaigns.
B．Drugs are more readily available and used by youth at a younger age than ever before.
C．Few parents warn their children often about the dangers of drugs.
D．Even policymakers, school officials find it necessary to reexamine current drug prevention efforts.

A．At the restaurant.
B．At the theatre.
C．At the station.
D．At the drugstore.