# $ % & ~ _ ^ \ { }在LaTex中属于特殊字符，要打印采用"\$"的方式
~ (tilde) unbreakable space, use it whenever you want to leave a space which is unbreakable, and cannot expand or shrink, as e.q. in names: A.~U.~Thor.
波浪线作为不可分割的连接
$ (dollar sign) to start an finish math mode.
美元数学模式
_ (underscore) for subscripts in math mode.
^ (hat) for superscripts in math mode.
上下标
\ (backslash) starting commands, which extend until the first non-alphanumerical character. The space following the command is swallowed. The following line results in what expected:
The \TeX nician is an expert in \TeX{} language.
转义
{} (curly brackets) to group and separate commands from its surroundings. Must appear in pairs.
&
The ampersand is used to separate items in the array and tabular Enviroments.
表格中的分隔符
#
The number (pound) sign is used to define use of arguments, for example
