转盘扭矩正常,泵压突然下降,井口流量减小,则其井下复杂情况为()。
A.溢流
B.井漏
C.井塌
D.砂桥
参考答案:B
My mother was very ______, she didn't approve of my hippie (嬉皮) lifestyle.[ ]
A. controversial
B. conventional
C. contradictory
D. contemporary
RNA分子中所含的碱基是______
A.GCTU B.GACT C.AGCU D.GATU E.TCAU