documentclass{cta-author}

newtheorem{theorem}{Theorem}{}
newtheorem{corollary}{Corollary}{}
newtheorem{remark}{Remark}{}
usepackage{blindtext}
usepackage{enumitem}
usepackage{array}
usepackage{mathrsfs}
usepackage{amsfonts}
usepackage{bm}
usepackage{tabularx}
usepackage{multirow}
usepackage{amsmath}
usepackage{graphicx}
usepackage{float}
usepackage{makecell}
usepackage{adjustbox}
usepackage{textcmds}
usepackage{lineno}
usepackage{rotating}

begin{document}


begin{table*}[t]
renewcommand{arraystretch}{1}
caption{C at PCC}
label{Table1}
centering
begin{tabular}{c|c|c|c|c|c|c|c|c}
 hline hline
 Standards &multicolumn{2}{c}{IEEE 2014}& multicolumn{2}{|c}{IEEE 2018}& multicolumn{2}{|c}{IEC 27} &multicolumn{2}{|c}{EN61-2}\ cline{2-4}

end{tabular}
end{table*}



end{document}