direct cut直接劈directadj.直接的；笔直的；坦白的v.对准；指挥；指示；命令directed line segment有向线段direct trading system直接交易制度direct shares holding直接持股direct-axis circuit顺轴电路Direct Reporting Unit直接报告装置direct lateral thrust直接侧向力direct cause of death直接死因direct esterification直接酯化direct current switch直流开关direct heated cathode直热式阴极