以下是完整的方程块：
\documentclass[12pt, English]{article}
\usepackage{amsfonts,amsmath,amssymb}
\usepackage{epsf, subfigure, verbatim, epsfig}
\usepackage{lineno, color}
\usepackage{geometry}
\geometry{verbose,letterpaper,tmargin=2.54cm,bmargin=2.54cm,
lmargin=2.54cm,rmargin=2.54cm}
\newtheorem{defi}{Definition}
\newtheorem{prop}{Proposition}
\newtheorem{theo}{Theorem}
\newtheorem{lemm}{Lemma}
\newtheorem{rema}{Remark}
\newtheorem{coro}{Corollary}
\DeclareMathOperator{\tr}{Tr}
\newcommand{\dsize}{\displaystyle}
\newcommand{\jdn}{\textcolor{blue}}
\newcommand{\njr}{\textcolor{red}}
\newcommand{\am}{\textcolor{NavyBlue}}
\newcommand{\dif}{\mathrm{d}}
\linenumbers
%\bibpunct{(}{)}{;}{p}{,}{,}
% Patch to fix line numbering problem
\newcommand*\patchAmsMathEnvironmentForLineno[1]{%
\expandafter\let\csname old#1\expandafter\endcsname
\csname #1\endcsname
\expandafter\let\csname oldend#1\expandafter\endcsname
\csnameend#1\endcsname
\renewenvironment{#1}%
{\linenomath\csname old#1\endcsname}%
{\csname oldend#1\endcsname\endlinenomath}}%
\newcommand*\patchBothAmsMathEnvironmentsForLineno[1]{%
\patchAmsMathEnvironmentForLineno{#1}%
\patchAmsMathEnvironmentForLineno{#1*}}%
\AtBeginDocument{%
\patchBothAmsMathEnvironmentsForLineno{equation}%
\patchBothAmsMathEnvironmentsForLineno{align}%
\patchBothAmsMathEnvironmentsForLineno{flalign}%
\patchBothAmsMathEnvironmentsForLineno{alignat}%
\patchBothAmsMathEnvironmentsForLineno{gather}%
\patchBothAmsMathEnvironmentsForLineno{multline}%
}
\begin{document}
\begin{titlepage}
Title
\end{titlepage}
\begin{abstract}
Abstract
\end{abstract}
\section{Model}
\begin{subequations} \label{eq:MainMod}
\begin{align}
x_1(n+1) &= \lambda_s x_1(n) + (1-\delta_m)\lambda_m x_2(n) + (1-
\delta_h)\lambda_h x_3(n) + \eta_s \lambda_c x_4(n)\\
& \hspace{5ex} + (1-\mu_s)\hat{x}_1(n,1) + \alpha_m (1-\mu_m)
\hat{x}_2(n,1), \nonumber\\
x_2(n+1) &= \eta_m \lambda_c x_4(n) + (1-\mu_m)(1-\alpha_m)\hat{x}_2(n,1),\\
x_3(n+1) &= \delta_h \lambda_h x_3(n) + \eta_h \lambda_c x_4(n) + (1-
\mu_h)\hat{x}_3(n,1) + \alpha_c (1-\mu_c) \hat{x}_4(n,1),\\
x_4(n+1) &= (1-\mu_c) (1-\alpha_c) \hat{x}_4(n,1),
\end{align}
\end{subequations}
\end{document}
并且它正常显示直到最后一行如下所示：
x_4(n+1) = (1-mu_c)(1-alpha_c)xhat_4(n,1),^9
（我可以附加一张截图吗？）
我尝试删除代码中最后一个术语后面的逗号，但是没有效果。