通常,大部分压力损失发生在钻井液通过()时。
A、地面高压管汇
B、地面高压管汇
C、钻头喷嘴
D、井下钻柱
参考答案:C
左心房肥大的心电图诊断包括()
A.P波峰距<0.04s
B.P波顶峰有明显切迹或双峰,峰距>0.04s
C.P波时限>0.12s
D.P波电压>0.25mV
E.V1Ptf<0.04mm·s
Though it’s not the 1st time that I ________ Beijing, I still can’t adjust myself to the weather.
A.been to
B.had been to
C.have been to
D.went to