单选题 Although buses are scheduled to depart at a certain hour, they are often late.
  • A. listed
  • B. required
  • C. obligated
  • D. located


【正确答案】 B
【答案解析】schedule在句中的意思为“预定”，对比四个选项的意思，A．listed“列单”；B．required“要求”；C．obligated“使负义务”；D．located“设立”，只有B项意思最接近，故应选B。