当油层有底水时，油井生产压差过大，会造成（）现象。
A、指进
B、单层突进
C、底水锥进
D、单向突进
参考答案：C
The research group ____________ 15 members has made great achievements in recent years.
A．is made up of
B．makes up
C．made up of
D．making up of
未婚妇女适用的妇科检查（）
A.窥器检查
B.双合诊
C.三合诊
D.肛查
E.肛腹诊
