表格测试

\[
\begin{tabular}{|l|c|r|r|}
  \hline
  kui & ng & oh & f... \\
  \hline
  asdf & 123 & $a^2+b^2$ & $\sum$ \\
  \hline
  $\frac12 & \sqrt{x} & \sqrt{\frac x{y+z}} & $\dfrac12$ \\
  \hline
\end{tabular}
\]

\begin{tabular}{|l|c|r|r|}
\hline
kui & ng & oh & f... \\
\hline
asdf & 123 & 123 & 4567 \\
\hline
\end{tabular}

\[
\begin{tabular}{|l|c|r|r|}
\hline
kui & ng & oh & f... \\
\hline
asdfadsf & 1234 & 1234 & 45678 \\
\hline
\end{tabular}
\]


\begin{tabular}{|l|c|r|r|}
\hline
kui & ng & oh & f... \\
\hline
asdfadsf & 1234 & 1234 & 45678 \\
\hline
\end{tabular}


\[
\begin{array}{|l|c|r|r|}
\hline
kui & ng & oh & f... \\
\hline
asdfadsf & 1234 & 1234 & 45678 \\
\hline
\end{array}
\]

\[
\left(\begin{array}{c|cc}
1&2&3\\
\hline
4&5&6\\
\end{array}\right)
\]

结果表明这里用不了 tabular，但 array 可以。