A-A+
They have been waiting for many hours. The air
问题详情
They have been waiting for many hours. The airplane must have been ______.
A．of schedule
B．on schedule
C．ahead of schedule
D．behind schedule
参考答案
正确答案：D
解析：本题测试介词短语的用法。根据题意，是指航班晚点，故应选behind schedule“落后于预定计划”。of schedule搭配不存在；on schedule“按时”；ahead of schedule“提前”。
