documentclass{article}

usepackage{todonotes}
usepackage{tabularx}
usepackage{array}
usepackage{arydshln}

begin{document}
    begin{tabular}{l l l }
        A & B & C
  end{tabular}

  begin{tabularx}{textwidth}{l X X}
        A & B & C
  end{tabularx}

end{document}