UPS电源电气性能表中规定:频率跟踪范围在()%以内可调。
A.50Hz±4%
B.50Hz±3%
C.50Hz±2%
参考答案:A
下列是右心衰症状,除了()
A.纳差、恶心
B.上腹胀痛
C.少尿
D.水肿
E.夜间阵发性呼吸困难
If you buy our goods, our company will ________ the goods to your door.[ ]
A.deliver
B.pass
C.show
D.work