I have advised him not to do like that, but he still insists on doing it that way. I think he has his own opinion _________.

A．above all

B．first of all

C．in all

D．after all

对工资主文件的更新是在一个实时系统中，由远程终端用户向一个主机结构程序发送。保证数据传输准确性的控制措施是：（）

A.回叫检测（echocheck）；

B.保护环；

C.杂项总和（hashtotal）；

D.整合测试设施。