宽带VSAT系统中前向信令采用（）广播方式。A.TDM B.FDM C.SCPC D

用质量为M的吸铁石，将一张质量为m的白纸压在竖直固定的磁性黑板上．某同学沿着黑板面，用水平向右的恒力F轻拉白纸，白纸未移动，则此时黑板对白纸的摩擦力的大小为(    )

A．F

B．mg

C．

D．

—What do you think the ___________should do first?

—They should learn to take ___________as well as share rights in life. 

A．grown-up;responsibility

B．growns-up;responsibility

C．grown-ups;responsibilities

D．growns-ups;responsibilities

The rescuers ________ to work as soon as they arrived at the spot of the accident.[ ]

A. set out  

B. set off

C. set up  

D. set in

目前驱动装置的电机有步进电动机，直流伺服电动机和交流伺服电动机等

本例中医辨证应为

A．风热感冒

B．暑湿感冒

C．燥邪犯肺

D．表寒里热

E．暑热证