19. (A) It makes them noisier than they were 20 years ago.

　　(B) It makes it difficult for them to fall asleep.

　　(C) It affects their work during the day.

　　(D) It does harm to their hearing.

　　20. (A) Many New Yorkers agree about banning this form of sonic pollution.

　　(B) The police have formed a posse to reduce the amount of noise.

　　(C) Police can break into a car as soon as the alarm goes off.

　　(D) Car alarms are very effective at preventing theft.