Which letter key on the keyboard should be used to switch from the selected state to the quick shielding state?

The preliminary basis of revision in F, B and Q. Knowing the characteristics of selection, selecting class toolset and alpha channel is helpful to establish selection quickly and accurately. To switch from the selected state to the quick shielding state, you should use the letter keys F, B and Q on the keyboard. Keyboard refers to a set of key switches with orderly functional circuits.