The first line will pop up a message on the control nodes' display (if X Window System is active), letting the user know that the laptop is inactive and needs to be powered down.

第一行将在控制节点的界面上弹出消息（如果 X Window System 处于活动状态），从而让用户知道笔记本处于非活动状态并且需要关闭。

youdao

And then in this case actually then X is 0. So the point, the original, the point with coordinates (0, 0) is on the line.

所以，这个点，坐标原点(0,0)在这条直线上。

youdao

To draw a guard on a sequence diagram in UML 1.x, you placed the guard element above the message line being guarded and in front of the message name.

UML 1 . x中，为了在一个序列图上画一个约束，你把约束元件放在约束的消息线上，消息名字之前。

youdao