关于隔离开关的作用,叙述正确的是()。
A.用于切断负荷电流
B.用于切断短路电流
C.切断小电流,隔离带电设备
D.仅起隔离作用,不能操作任何电流
参考答案:C
Food supplies in the floodstricken area ________. We must act immediately before there's none left. [ ]
A. have run out
B. are running out
C. have been run out
D. are being run out
妊娠足月时的羊水比重>1.025。