发票的准备和邮寄属于订单履行环节的工作。
参考答案：对
Exercise helps ______. [ ]
A. to keep health
B. to keep in good health
C. keeping healthy
在远动装置接收信道上收到信号电压为0.4V，此值相当于（）dBm。
A.0.4
B.12
C.-6.47
D.-5.74
