在结构化方法开发的整个过程中,最重要的环节是( )。
A.需求分析和需求定义
B.系统规划和可行性分析
C.系统逻辑模型的确定
D.系统物理模型的确定
参考答案:A
All these gifts must be mailed immediately in time for Christmas. [ ]
A.in order to have received
B.in order to receive
C.so as to be received
D.so as to be receiving
两井定向与一井定向相比,具有()等特点。
A.外业操作简单
B.投向误差显著减小
C.测角误差减小
D.占用井筒时间较少
E.量边误差减小