枚舉文件的某些部分

Question

摘要不應該是枚舉，內容列表應該從I（羅馬數字）開始，第一章應該從1（普通數字）開始，怎麼製作？

\documentclass[11pt,letterpaper]{report}    
%\usepackage{etoolbox}
\usepackage{titlesec}

\begin{document}
{
\titleformat{\chapter}[block]{\filcenter\Huge\bfseries}{}{0pt}{}
\titlespacing{\chapter}{0pt}{0pt}{40pt}
\chapter*{ABSTRACT}
}

%\chapter*{\makebox[\linewidth]{ABSTRACT}}%\chapter*{\centering Abstract}
El principal mecanthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis intro

\section{Exp}
this Exp SECTION
\tableofcontents
\chapter{ETAPA2}
\label{cap:experimental}
this intro

\section{Exp2}
this Exp SECTION

\end{document}

Answer 1

基於https://tex.stackexchange.com/a/408118/36296你可以這樣做：

\documentclass[11pt,letterpaper]{report}    
%\usepackage{etoolbox}
\usepackage{titlesec}

\newcommand\frontmatter{%
  \cleardoublepage
  % \@mainmatterfalse
  \pagenumbering{roman}
}

\newcommand\mainmatter{%
    \cleardoublepage
    % \@mainmattertrue
    \pagenumbering{arabic}
  }

\newcommand\backmatter{%
  \if@openright
    \cleardoublepage
  \else
    \clearpage
  \fi
  % \@mainmatterfalse
}


\begin{document}

{
\titleformat{\chapter}[block]{\filcenter\Huge\bfseries}{}{0pt}{}
\titlespacing{\chapter}{0pt}{0pt}{40pt}
\chapter*{ABSTRACT}
}
\thispagestyle{empty}
%\chapter*{\makebox[\linewidth]{ABSTRACT}}%\chapter*{\centering Abstract}
El principal mecanthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis intro

\section{Exp}
this Exp SECTION

\frontmatter
\tableofcontents

\mainmatter
\chapter{ETAPA2}
\label{cap:experimental}
this intro

\section{Exp2}
this Exp SECTION

\end{document}