在驻波比测试仪的测试口“TESTPORT”严禁加入超出（）dBm的任何信号电平或40V直流信号
参考答案：+20
They would be good friends _____ he saw her at the party. [ ]
A. for the first time
B. first time
C. the first time
D. it's the first time
任何机器在拆卸前必须切断电源，并挂上警告的标志。
