ショートカットを発動させるために、ボタンを順番に押すのはいつで、同時に押すのはいつですか？

[pfaffman (Jay Pfaffman)]

Control, alt, and shift are modifiers. If you press and release them, in, say, your word processor, nothing happens.

If the key does something by itself, then you press and release it.

Edit: oh, but I get that the documentation should be clearer.