marking of drill pipe

例句：

1. 1. The artist drew a marking on the wall to indicate the spot where he had painted.
   艺术家在墙上画了一个标记，以指示他绘画的地点。
2. 2. The teacher marked the exam papers with a pen for easy identification.
   老师用笔在试卷上做了标记以便容易辨认。
3. 3. The conductor marked the timetable on the scoreboard.
   指挥家在计分板上做了时间安排的标记。