signal和sign的区别

sign通常用作数学符号、物理符号等。signal就是一种向进程传递信息的方式，可以将信号想象成大楼的管理员往房间的信箱里塞小纸条。

He signaled the waiter to bring the menu.

他做手势要侍者拿菜单来。

The conductor signaled the orchestra to rise.

指挥打手势让乐队起立。

Jim signaled his helplessness to Mary to leave the party.

吉姆无法从宴会脱身时，他向玛丽使了个眼色，表示无可奈何。

She had a silver peace symbol hanging on a chain around her neck.

她有一个银制的和平标志挂在项链上。

She put her finger to her lips as a sign to be quiet.

她将手指放在唇上表示应安静。

He gave his wife a ring as a token of his love.

他给他爱人一枚戒指，作为爱情的象征。