油水界面分析．要特别注意分析油水过渡带（）问题。
A、孔隙度
B、地层压力
C、渗透率
D、原油外流
参考答案：D
On,June the 25th, 2009, Michael Jackson made his final exit from this earthly stage, leaving the whole world________.
A．shocked.
B．shocking
C．being shocked
D．having shocked
水准仪观测时，应尽可能使前后视距离相等，视线长度以（）为宜。
A.50～70m
B.50～80m
C.50～100m
D.50～200m
