一个RB由若干个RE组成，频域宽度为180kHz，时间长度为0.5ms
参考答案：对
—Why do you get up so early in the morning,Tracy?
—I generally make it a _________to be up by 7 to read English.[ ]
A. plan
B. wish
C. secret
D. rule
悲忧过度主要损伤的脏腑是( )
A．肝B．心C．脾D．肺E．肾
