控制键，又名Ctrl键。普遍有两颗，多数字于左下及右下角；亦有一些键盘只设有一颗Ctrl键。

In computing, a Control key is a modifier key which, when pressed in conjunction with another key, performs a special operation (for example, Ctrl+C); similar to the Shift key, the Control key rarely performs any function when pressed by itself. The Control key is located on or near the bottom left side of most keyboards (in accordance with the international standard ISO/IEC 9995-2), with many featuring an additional one at the bottom right.