如何刪除某一特定章節標題之前的垂直空間？

Question

怎麼把整章拉高？其他章節不要修改，我只想上傳第一章。

\documentclass{book}
\usepackage{etoolbox}

\begin{document}

\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

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

\section{Exp2}
this Exp SECTION

\end{document}

我想要這個結果：

Answer 1

titlesec按照@JouleV的建議使用該包：

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

完整程式碼

\documentclass{book}
%\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

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

\section{Exp2}
this Exp SECTION

\end{document}