YT Lee's simple notes

Commands:

\begin{flushleft}    \end{flushleft} - to typeset the text between them exactly at the left of the page. 靠左
\begin{flushright}    \end{flushright} - to typeset the text between them exactly at the right of the page. 靠右
\begin{center}    \end{center} - to typeset the text between them exactly at the center of the page. 置中

Example:

\begin{flushleft}First line.\\[10pt] Second Line.\end{flushleft}
\begin{flushright}Third line.\\[10pt] Fourth Line.\end{flushright}
\begin{center}Fifth line.\\[10pt] Sixth Line.\end{center}

Result: