该gb4e软件包可帮助语言学家翻译示例。它使用列表环境将示例与正文分开。语言科学出版社版本的该软件包使用\ea和\eal作为简写。（这些命令在原始软件包中，但被注释掉并声明为谨慎使用）。使用简写更易于阅读和维护。问题：有没有办法减少第二个脚注（第 3 页）中 (i) 和 (ii) 之间的空间，使其看起来像 (iii) 和 (iv)，但编写示例的语法与 (i) 和 (ii) 相同？
\documentclass[12pt]{scrbook}
\usepackage{gb4e}
\usepackage{gb4e}
\makeatletter
\def\eal{\begin{exe}\exnrfont\ex\begin{xlist}[iv.]\raggedright}
\def\ex{\@ifnextchar [{\exnrfont\@ex}{\exnrfont\item\exfont}}
\def\eal{\begin{exe}\exnrfont\ex\begin{xlist}[iv.]\raggedright}
\def\z{\ifnum\@xnumdepth=1\end{exe}\else\end{xlist}\fi}
\def\zl{\end{xlist}\end{exe}}
\makeatother
\newcommand{\exnrfont}{\exfont\upshape}
\newcommand{\exfont}{\normalsize\upshape}
\usepackage{blindtext}
\begin{document}
\blindtext
\eal
\ex This is an example.
\ex This is another example.
\zl
\eal
\ex This is an example in another set.
\ex This is another example in another set.
\zl
\blindtext\footnote{
\blindtext
\eal
\ex This is an example.
\ex This is another example.
\zl
\eal
\ex This is an example in another set.
\ex This is another example in another set.
\zl
\blindtext
}
\blindtext
\pagebreak
\blindtext
\ea
This is an example.
\z
\ea
This is an example in another set.
\z
\blindtext\footnote{
\blindtext[1]
\ea
This is an example.
\z
\ea
This is an example in another set.
\z
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis sem. Nullam
nec mi et neque pharetra sollicitudin. Praesent imperdiet mi nec ante. Donec ullamcorper,
felis non sodales commodo, lectus velit ultrices augue, a dignissim nibh lectus placerat
pede.
\ea
This is an example.
\ex
This is an example in another set.
\z
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis sem. Nullam nec mi et neque pharetra sollicitudin. Praesent imperdiet mi nec ante. Donec ullamcorper, felis non sodales commodo, lectus velit ultrices augue, a dignissim nibh lectus placerat pede.
}
\blindtext
\end{document}