在不分散低固相钻井液中，钻井液密度升高产生的静液压力增大，钻速（）。
A、升高
B、降低
C、不变
D、不一定
参考答案：B
按JJG667-97，容积式流量计的检定周期为（）。按JJG198-94，速度式流量计的检定周期为（）。
— Did you go to the beaches?
— No, mum is ill _____ and I _____ stay at home to look after her. [ ]
A. on bed; must
B. on the bed; have to
C. in the bed; must
D. in bed; have to
