# Construct a table in Beamer

I'm using LuaLaTex to make my slide. There is a table in my slide. However, i can't control the size and some parts of the table can't be vievew. How can I solve this issue?

\documentclass[11pt]{beamer}

\begin{document}

\begin{frame}{Plan for completion and thesis submission}

%%
\begin{center}

%%
\begin{tabular}{|l|c|c|c|c|c|}
\hline
\centering{Tasks} & \multicolumn{2}{|c|}{\small{2016/2017}} & \multicolumn{2}{|c|}{\small{2017/2018}} & \small{2018/2019}\\
\cline{2-6}
& \tiny{Sem. 1} & \tiny{Sem. 2} & \tiny{Sem. 1} & \tiny{Sem. 2} & \tiny{Sep - Dec 18} \\

\hline
\small{Reading and understanding}       & $\times$ &   $\times$      &       &           &\\
\small{of various advanced concepts}    &        &        &       &           &\\
\small{on groups and graphs}               &        &        &        &           &\\

\hline
\small{Write a literature review}           & $\times$  &       &         &           &\\

\hline
\small{Obtain examples (by hand}       &         & $\times$ &         &           &\\
\small{or using a computational}         &          &       &         &            &\\
\small{algebra system)}                     &          &       &         &             &\\

\hline
\small{Form conjectures and}             &          & $\times$ &        &             &\\
\small{prove or disprove the}             &          &        &         &            &\\
\small{conjectures}                           &          &        &         &             &\\

\hline
\small{Work on}             &           &  $\times$    &$\times$     & $\times$      & $\times$\\
\small{research problems}                &           &      &           &             &\\

\hline
\small{Submit a paper to an}            &           &       & $\times$    &             &\\
\small{ISI-indexed journal for}         &           &        &          &             &\\
\small{publication}                          &           &        &          &             &\\

\hline
\small{Write up thesis for}               &           &        &          &$\times$ &\\
\small{submission}                          &           &        &          &              &\\

\hline
\small{Complete writing up}            &           &         &          &             & $\times$ \\
\small{of thesis and submit}            &           &         &          & &\\
\small{thesis by December 2018}    &           &         &           &  &\\
\hline

\end{tabular}

\end{center}

\end{frame}

\end{document}


To save some space, both horizontally and vertically, use a smaller font size, employ less whitespace between columns, and make the headers terser. To assure that the tabular material fits within the textblock, use a tabularx environment and the X column type for the first column. If you use an X column for the first column, you can also employ it to perform automatic line breaking.

Separately, do try to give the table a more "open" look. E.g., get rid of all vertical lines -- they're not needed! really! -- and use fewer, but well-spaced horizontal lines. I recommend using the macros of the booktabs package.

\documentclass[11pt]{beamer}
\usepackage{tabularx,ragged2e,booktabs}
\begin{document}

\begin{frame}{Plan for completion and thesis submission}

\footnotesize
\setlength\tabcolsep{4pt} % default: 6pt
\begin{tabularx}{\textwidth}{@{}>{\RaggedRight}X*{5}{c}@{}}
\toprule
Tasks & \multicolumn{2}{c}{2016--17} & \multicolumn{2}{c}{2017--18} & 2018--19\\
\cmidrule(l){2-6}
& {\tiny Sem.\ 1} & {\tiny Sem.\ 2} & {\tiny Sem.\ 1} & {\tiny Sem.\ 2} & {\tiny Sep--Dec 18} \\
\midrule
& $\times$ & $\times$  \\
Write a literature review
& $\times$ \\
Obtain examples (by hand or using a computational algebra system)
& & $\times$ \\
Form conjectures and prove or disprove the conjectures
& & $\times$ \\
Work on research problems
& & $\times$ &$\times$ & $\times$ & $\times$ \\
Submit a paper to an ISI-indexed journal for publication
& & & $\times$ \\
& & & &$\times$ \\
& & & & & $\times$ \\