单项选择题
A.10S B.20S C.30S D.40S
A.小明的手机型号太老旧了 B.双频网关WIFI坏了 C.测速软件选择不正确 D.网关摆放位置不正确
A.0-10mm B.10-30mm C.30-50mm D.50-70mm