答案1
我已经完成了创建新计数器和定义新命令的操作:
\documentclass[a5paper]{article}
\usepackage{bigfoot}
\DeclareNewFootnote{default}
\newcounter{footalt}[footnote]
\def\thefootalt{\thefootnote \alph{footalt}}
\def\footnoteA{\refstepcounter{footalt}%
\Footnotedefault{\thefootalt}}
\begin{document}
Hello.\footnote{usual footnote} This\footnote{second usual footnote} is a
test.\footnoteA{ sub footnote}
This is a test.\footnoteA{ sub footnote} This is a test. This is a test.
\end{document}