Update chapters/classes.tex

Co-authored-by: Henrik Tidefelt <henrikt@wolfram.com>

chapters/classes.tex

@@ -357,7 +357,7 @@ \subsection{Component Variability Prefixes}\label{component-variability-prefixes
   A variable \lstinline!vc! declared with \lstinline!constant!\indexinline{constant} prefix remains constant during simulation, with a value that is unaffected even by the initialization problem.
   This is called a \firstuse[---]{constant}, or \firstuse[constant!variable]{constant variable}\index{component variability!constant}.
 \item
-  A variable \lstinline!vc! declared with the \lstinline!parameter!\indexinline{parameter} prefix has its value determined by the initialization problem, and has that value during the entire simulation.
+  A variable \lstinline!vc! declared with the \lstinline!parameter!\indexinline{parameter} prefix has a value determined by the initialization problem, and keeps that value during the entire simulation.
   This is called a \firstuse[---]{parameter}, or \firstuse[parameter!variable]{parameter variable}\index{component variability!parameter}.
 \item
   A \firstuse[discrete-time!variable]{discrete-time variable}\index{component variability!discrete-time} \lstinline!vd! is a variable that is discrete-valued (that is, not of \lstinline!Real! type) or assigned in a \lstinline!when!-clause.