（）是确保工作票正确实施的最终责任部门。
A.运行、检修主管部门
B.安全监督部门
C.技术监督部门
D.生产部门
参考答案：A
如果运费支付方没有支付运费，承运人在交货之前只能对不同航程、不同运输合同的货物实行留置权。( )
A certain clock marks every hour by striking a number of times equal to the hour and the time required for a stroke is exactly equal to the time interval between strokes. At 6:00 the time lapse between the beginning of the first stroke and the end of the last stroke is 22 seconds. At 12:00, how many seconds elapse between the beginning of the first stroke and the end of the last stroke ？（）
A．72
B．50
C．48
D．46
E．44
