麻痹性肠梗阻病人常首先发生()
A.低渗性脱水
B.高渗性脱水
C.等渗性脱水
D.水肿
E.水中毒
参考答案:C
He ___________ the volunteer group last year and ___________ many activities since then.
A. took part in…joined B. joined…took part in C. joined…has taken part in
在接地网中,带有保护接地的电气设备,当发生相线碰壳故障时,若人体接触设备外壳,保证不会发生触电事故。