引鞋在套管柱的最下端，引导钻具进入套管，防止钻具接头碰挂套管底部。（）
参考答案：错
— ______ desk is this?
— It's ______. [ ]
A Who's, Sandy's and Simon's
B. Whose, Sandy's and Simon's
C. Who's, Sandy and Simon's
D. Whose, Sandy and Simon's
出口加工区运往境内，区外维修、测试的机器设备，应自运出之日起______运回加工区。
A．1个月
B．2个月
C．3个月
D．6个月
