插入模式

Make Corrections Instantly from Insert Mode

Meet Insert Normal Mode

e.g. <C-o>zz

Get Back to Normal Mode

Paste from a Register Without Leaving Insert Mode

The <C-r><C-p>{register} command is smarter. It inserts text literally and fixes
any unintended indentation (see :h i_CTRL-R_CTRL-P ).

Do Back-of-the-Envelope Calculations in Place

Insert Unusual Characters by Character Code

例子：
<C-v>{code}: <C-v>065
<C-v>u{1234}: <C-v>u00bf
See :h i_CTRL-V_digit for more details.

Insert Unusual Characters by Digraph

Digraphs are easy to use. From Insert mode, we just type <C-k>{char1}{char2}.
So if we wanted to insert the “¿” character, which is represented by the digraph
?I, we would simply type <C-k>?I.

The character pairs that make up a digraph are chosen to be descriptive,
making them easier to remember or even guess. For example, the doubleangle quotation marks « and » are represented by the digraphs << and >>;
the vulgar (or common) fractions ½, ¼, and ¾ are represented by the digraphs
12, 14, and 34, respectively. The default set of digraphs that ship with Vim
follows certain conventions, which are summarized under :h digraphs-default .
We can view a list of the available digraphs by running :digraphs, but the output
of this command is difficult to digest. A more usable list can be found by
looking up :h digraph-table .