只要是平面法兰,缠绕垫片可以用于压力等级相同的任何介质、任何温度下的法兰面密封。()
参考答案:对
Joy _______ as a language teacher in China for two years before she went back to London.
A.had worked
B.was working
C.worked
D.has worked
失代偿性呼吸性酸中毒时,血气分析及血清电解质的改变是()
A.PaCO2升高、pH升高、血钾升高
B.PaCO2升高、pH降低、血钾升高
C.PaCO2升高、pH降低、血氯升高
D.PaCO2升高、pH升高、血氯降低
E.PaCO2升高、pH升高、血氯血钾正常