terms of VIM

• white space

  either space, tab, and EOL.

• word

  a sequence of characters containing only a-zA-Z0-9_.

• WORD

  a sequence of all characters except white space.

• sentence

  ends with either . ! ? followed by a white space.

• paragraph

  begins after each empty line and also at each set of a paragraph macro specified by the pairs of characters in paragraphs option.

  A paragraph begins and ends after an empty line.

  一个段落可以从一个空行之后开始，也可以从段落选项(paragraphs)中"字符对"所指定的段落宏的每个集合开始。