为执行基本作业而进行的各项辅助操作所消耗的时间为（）。A、辅助时间 B、基本作业时间

30. ---__________you got to know so much about the pop group in America?

---Through the Internet.

A．How was it

B．What was it

C．How was it that

D．What was it that

So confused ______ that he didn't know how to start his lecture.[ ]

A. since he became

B. would he become  

C. that he became    

D. did he become

最早使用心理应激概念学者是()

A．Selye

B．Kobassa

C．Ellis

D．Masson

E．Cannon

下列哪种情形不能够运用“气体流速与压强关系”进行解释 　 [     ]

A． 乒乓球运动员拉出的弧圈球能急速旋转而下沉　

B． 将氢气球放手后，它会漂向空中　

C． 飞机升空　

D． 船舶航行时应避免两艘靠近的船并排前进

阐述测试SDH输出口信号比特率时的操作步骤。