VIM：可映射(未使用)快捷键？

1.7 WHAT KEYS TO MAP                                    *map-which-keys*

If you are going to map something,you will need to choose which key(s) to use
for the {lhs}.  You will have to avoid keys that are used for Vim commands,otherwise you would not be able to use those commands anymore.  Here are a few
suggestions:
- Function keys <F2>,<F3>,etc..  Also the shifted function keys <S-F1>,<S-F2>,etc.  Note that <F1> is already used for the help command.
- Meta-keys (with the ALT key pressed). |:map-alt-keys|
- Use the '_' or ',' character and then any other character.  The "_" and ","
  commands do exist in Vim (see |_| and |,|),but you probably never use them.
- Use a key that is a synonym for another command.  For example: CTRL-P and
  CTRL-N.  Use an extra character to allow more mappings.

See the file "index" for keys that are not used and thus can be mapped without
losing any builtin function.  You can also use ":help {key}^D" to find out if
a key is used for some command.  ({key} is the specific key you want to find
out about,^D is CTRL-D).