例如：
\begin{longtable} { |L{2.75cm}|c|c|c|c| }
如果居中列的宽度已经固定，我可以写入任何内容（写入 2.75cm）来使第一列的宽度使得表格在其边距内占据页面的整个宽度？
MWE 使用 xltabular 代替 longtable （无法编译）：
\documentclass[12pt, a4paper]{report}
\usepackage[utf8]{inputenc}
\usepackage{graphicx}
\usepackage{amsmath}
\usepackage{float}
\setlength{\parskip}{1em}
\usepackage[a4paper, total={6in, 8in}]{geometry}
\graphicspath{ {images/} }
\newcommand{\degree}{\ensuremath{^\circ}}
\newcommand{\quotes}[1]{``#1''}
\setlength\parindent{0pt}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{imakeidx}
\makeindex[columns=3, title=Alphabetical Index, intoc]
\usepackage[spanish,es-nodecimaldot]{babel}
\usepackage[sorting=none]{biblatex}
\addbibresource{Bibfile.bib}
\DeclareMathOperator\grad{grad}
\DeclareMathOperator\prima{'}
\DeclareMathOperator\sen{sen}
\usepackage{array}
\usepackage{tabularx}
\usepackage{lscape}
\usepackage{caption}
\captionsetup[table]{position=bottom}
\usepackage{booktabs}
\usepackage{mathptmx}
\usepackage[per-mode=symbol]{siunitx}
\usepackage{bm}
\usepackage{amsmath}
\newcolumntype{L}[1]{>{\raggedright\arraybackslash}p{#1}}
\newcolumntype{C}[1]{>{\centering\arraybackslash}p{#1}}
\usepackage{longtable}
\interfootnotelinepenalty=10000
\usepackage[spanish]{minitoc}
\usepackage{hyperref}
\usepackage{siunitx}
\sisetup{group-digits=false}
\usepackage{mathtools, nccmath}
\usepackage[raggedright]{titlesec}
\mathchardef\mhyphen="2D
\usepackage{xltabular}
\title{Tabla 1}
\author{-}
\date{September 2021}
\begin{document}
\maketitle
\section{Introduction}
\begin{xltabular}{ |X|c|c|c|c| }
\caption[Datos del tren de aterrizaje de aviones semejantes.]{\label{tren}}
\endlastfoot
\hline
\multicolumn{5}{|c|}{\textbf{Tren de Aterrizaje}} \\
\hline
& Proyecto & \vtop{\hbox{\strut \makebox[2.5cm][c]{A319-100}\par }\hbox{\strut \makebox[2.5cm][c]{\cite{A319APM,JanesA319,A319TC,EurocontrolA319}}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{B737-700}\par }\hbox{\strut \makebox[2.5cm][c]{\cite{B737APM,JanesB737,B737TC,EurocontrolB737}}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{A220-300}\par }\hbox{\strut \makebox[2.5cm][c]{\cite{A220APM,JanesA220,A220TC,EurocontrolA220}}\par}} \\
\hline
Tipo & \vtop{\hbox{\strut \makebox[1cm][c]{Triciclo}\par }\hbox{\strut \makebox[1cm][c]{retráctil}\par}} & \vtop{\hbox{\strut \makebox[1cm][c]{Triciclo}\par }\hbox{\strut \makebox[1cm][c]{retráctil}\par}} & \vtop{\hbox{\strut \makebox[1cm][c]{Triciclo}\par }\hbox{\strut \makebox[1cm][c]{retráctil}\par}} & \vtop{\hbox{\strut \makebox[1cm][c]{Triciclo}\par }\hbox{\strut \makebox[1cm][c]{retráctil}\par}} \\
\hline
Vía\footnote{La vía $T$ del tren de aterrizaje es la distancia entre el centro de las huellas de los trenes principales. Si son más de dos, tomamos los más alejados del plano de simetría del avión.} $T$ (m) & 6.9338 & 7.59 & 5.72 & 6.73 \\
\hline
Batalla\footnote{La batalla $B$ del tren de aterrizaje es la distancia longitdinal entre el centro de la huella del tren auxiliar y los centros de las huellas de los trenes principales. Si hay más de dos tomamos los de mayor distancia longitudinal respecto al tren auxiliar.} $B$ (m) & 12.7734 & 11.039 & 12.6 & 14.63 \\
\hline
Relación $T/B$ & 0.5428 & 0.6869 & 0.4540 & 0.4600 \\
\hline
Relación $T/b$ & 0.1995 & 0.2226 & 0.1667 & $\sim$ 0.2093 \\
\hline
Relación $B/{l_f}$ & 0.3653 & 0.3262 & 0.3915 & 0.3781 \\
\hline
Número de neumáticos por pata\footnote{Para los datos de las patas del tren de aterrizaje, usamos el subíndice $p$ para referirnos a las patas del tren principal, y el subíndice $a$ para referirnos al tren auxiliar.} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$N_p = 2$}\par}\hbox{\strut \makebox[2.5cm][c]{$N_a = 2$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$N_p = 2$}\par}\hbox{\strut \makebox[2.5cm][c]{$N_a = 2$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$N_p = 2$}\par}\hbox{\strut \makebox[2.5cm][c]{$N_a = 2$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$N_p = 2$}\par}\hbox{\strut \makebox[2.5cm][c]{$N_a = 2$}\par}} \\
\hline
Denominación del neumático & \vtop{\hbox{\strut \makebox[3.25cm][c]{Pr: H42x16-19}\par}\hbox{\strut \makebox[3.25cm][c]{Aux: 25.75x6.75-14}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{Pr: 46x16-20}\par}\hbox{\strut \makebox[2.5cm][c]{Aux: 30x8.8-15}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{Pr: 43.5x16-21}\par}\hbox{\strut \makebox[2.5cm][c]{Aux: 27x7.7-15}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{Pr: 42x15-21}\par}\hbox{\strut \makebox[2.5cm][c]{Aux: 27x8.5-12}\par}} \\
\hline
Diámetro (m) & \vtop{\hbox{\strut \makebox[2.5cm][c]{$D_p = 1.0668$}\par}\hbox{\strut \makebox[2.5cm][c]{$D_a = 0.6541$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$D_p = 1.1784$}\par}\hbox{\strut \makebox[2.5cm][c]{$D_a = 0.762$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$D_p = 1.1049$}\par}\hbox{\strut \makebox[2.5cm][c]{$D_a = 0.6858$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$D_p = 1.0668$}\par}\hbox{\strut \makebox[2.5cm][c]{$D_a = 0.6858$}\par}} \\
\hline
Ancho (m) & \vtop{\hbox{\strut \makebox[2.5cm][c]{$b_p = 0.4064$}\par}\hbox{\strut \makebox[2.5cm][c]{$b_a = 0.1715$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$b_p = 0.4064$}\par}\hbox{\strut \makebox[2.5cm][c]{$b_a = 0.2235$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$b_p = 0.4064$}\par}\hbox{\strut \makebox[2.5cm][c]{$b_a = 0.1956$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$b_p = 0.381$}\par}\hbox{\strut \makebox[2.5cm][c]{$b_a = 0.2159$}\par}} \\
\hline
Presión de inflado (MPa) & \vtop{\hbox{\strut \makebox[2.5cm][c]{$p_p = 1.31$}\par}\hbox{\strut \makebox[2.5cm][c]{$p_a = 1.372$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$p_p = 1.19$}\par}\hbox{\strut \makebox[2.5cm][c]{$p_a = 1.14$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$p_p =$ 1.36 - 1.41}\par}\hbox{\strut \makebox[2.5cm][c]{$p_a = 1.42$}\par}} & \vtop{\hbox{\strut \makebox[2.5cm][c]{$p_p = 1.47$}\par}\hbox{\strut \makebox[2.5cm][c]{$p_a = 1$}\par}} \\
\hline
\end{xltabular}
\printbibliography
\end{document}
答案1
环境xltabular需要两个必需参数：预期宽度和列规范集。您的代码省略了两个必需参数中的第一个。
此外，如果您没有，请不要忘记在之前立即\parindent0pt插入。\noindent\begin{tabularx}{\textwidth}{...}