\documentclass[a4paper]{article}
%\usepackage{syntonly}
%\syntonly

\pagestyle{headings}
%define the title
\author{wwate shen}
\title{\LaTeXe{}\_\TeX{}\_\LaTeX{}}
\begin{document}
%generates the tile
\maketitle
%insert the table of contents
\tableofcontents
\section{PartI}
Hello, world!  
\section{PartII}
Small is \textsl{beautiful}!
\ldots{} and here is end.
\\
http://www.sohu.com/$\sim$demo\\
Its $-30 \,^{\circ}\mathrm{C}$,
Super-conductor \footnote{Just hasn't \ldots}
is good for us now.\\
Not like this ... but like this:\\
New York, Tokyo, Budapest, \ldots\\
\emph{If you use emphasizing inside a piece of emphasized test, 
then \LaTeX{} uses the \emph{normal} font for emphasizing.}\\

\textit{You can also \emph{emphasize} text 
if it is set in italics, }
\textsf{in a \emph{sans-serif} font,}
\texttt{or in \emph{typewriter} style.}\\
\newpage
\center
\begin{enumerate}
\item Mixing the list environments
\begin{itemize}
\item But it might start
\item[-] hehe
\end{itemize}
\item Therefore remember:
\begin{description}
\item[stupid] things will die \ldots
\item[smart] pig will come into being
\end{description}
\end{enumerate} 
\begin{center}
At the center\\of the earth
\end{center}
\flushleft
A typographical rule of thumb
for the line length is:
\begin{quote}
On average, no line should
be longer than 66 characters.
\end{quote}
This is why \LaTeX{} pages have
such large borders by default and
also why multicolumn print is
used in newspapers.
\begin{verse}
Humpty Dumpty sat on a wall:\\
Humpty Dumpty had a great fall.\\
All the King's horses and all
the King's men\\
Couldn't put Humpty together
again.
\end{verse}
The \verb|\TeX{}| is here:
\begin{verbatim*}
10    PRINT "hello world"
20    GOTO 10
\end{verbatim*}
\begin{tabular}{c r @{.} l}
Pi expression	&
\multicolumn{2}{c}{value}\\
\hline
$\pi$		&3&1415926 \\
$\pi^{\pi}$	&36&46 \\
$(\pi^{\pi})^{\pi}$ & 8066&1234 \\
\end{tabular}
\\
\begin{tabular}{|c|c|}
\hline
\multicolumn{2}{|c|}{Ene} \\
\hline
Mene & Muh! \\
\hline
\end{tabular}
Figure\verb|\ref{white}| is an example.
\begin{figure}[!hbp]
%\makebox[\textwidth]{\framebox[5cm]{\rule{Opt}{5cm}}}
\caption{Five by Five in Centimeters.} %\label{white}
\end{figure}
\newpage
\flushleft
%Example 1
\ldots when Einstein introduced his formula
\begin{equation}
e = m \cdot c^2 \; ,
\end{equation}
which is at the same time the most widely known
and the least well understood physical formula.
\newline
% Example 2
\ldots from which follows Kirchoffs current law:
\begin{equation}
\sum_{i=1}^{n} I_i = 0 \; .
\end{equation}
\\
% Example 3
\ldots which has several advantages.
\begin{equation}
I_D = I_F - I_R
\end{equation}
is the core of a very different transistor model. \ldots

\end{document}