我正在尝试在我的 main.tex 中导入 xparse 包以便能够使用包子文件。
\documentclass{book}
\usepackage[a4paper,margin=3cm]{geometry}
\usepackage{xparse}
\usepackage{subfiles}
但是当我尝试使用 进行编译时latex main.tex，出现错误：
This is pdfTeX, Version 3.14159265-2.6-1.40.16 (TeX Live 2015/Debian) (preloaded format=latex)
restricted \write18 enabled.
entering extended mode
(./main.tex
LaTeX2e <2016/02/01>
Babel <3.9q> and hyphenation patterns for 3 language(s) loaded.
(/usr/share/texlive/texmf-dist/tex/latex/base/book.cls
Document Class: book 2014/09/29 v1.4h Standard LaTeX document class
(/usr/share/texlive/texmf-dist/tex/latex/base/bk10.clo))
(/usr/share/texlive/texmf-dist/tex/latex/geometry/geometry.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/ifpdf.sty)
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/ifvtex.sty)
(/usr/share/texlive/texmf-dist/tex/generic/ifxetex/ifxetex.sty))
(/usr/share/texlive/texmf-dist/tex/latex/l3packages/xparse.sty
(/usr/share/texlive/texmf-dist/tex/latex/l3kernel/expl3.sty
(/usr/share/texlive/texmf-dist/tex/latex/l3kernel/expl3-code.tex
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !
Argh, internal LaTeX3 error!
Module kernel, message name "command-already-defined":
Arguments '\@@_use_none_delimit_by_q_recursion_stop:w' and '\long macro:#1\q_@@
_recursion_stop ->'
This is one for The LaTeX3 Project: bailing out.
\__kernel_msg_error:nnxx ... Project: bailing out}
\tex_end:D
l.2940 ...@_use_none_delimit_by_q_recursion_stop:w
知道我做错了什么吗？既然它是第一个加载的包之一，那么命令怎么可能已经被定义了？