21. According to _______announcement by Guangzhou Price Bureau, _______new measures which have been taken recently are expected to cut the operation costs of each taxi driver by 1280 yuan.

   A. the; /           B. an; the          C. /; the           D. an; /

22. This machine __________ It has worked for years.

  A. didn’t work     B .wasn’t working    C. doesn’t work    D. isn’t working