catch points sign

例句：

1. 1. The engineer used a special device to catch the points on the screen.
   工程师使用一种特殊的设备来捕捉屏幕上的点。
2. 2. The teacher gave us a signal to start the experiment.
   老师给我们一个信号开始实验。
3. 3. The car's dashboard has several marks indicating speed limits.
   汽车的仪表盘上有多个标记指示速度限制。