#!/usr/bin/perl
$_='{\selectlanguage{english}
\textcolor{black}{\ \ 10.\ \ Three resistors connected in series each
carry currents labeled }\textit{\textcolor{black}{I}}\textcolor{black}{\textsubscript{1}}\textcolor{black}{,
}\textit{\textcolor{black}{I}}\textcolor{black}{\textsubscript{2}}\textcolor{black}{and}\textit{\textcolor{black}{I}}\textcolor{black}{\textsubscript{3}}\textcolor{black}{.
Which of the following expresses the value of the total current
}\textit{\textcolor{black}{I}}\textit{\textcolor{black}{\textsubscript{T}}}\textcolor{black}{in the system made up of the three resistors in series?}}.';;
$nobrackets  = qr/[^\{}]+/;  
my $pass = 0;
while(++$pass <=2){
s/\\textsuperscript\{($nobrackets)\}/ startsuperscript $1 endsuperscript /g;
s/\\textsubscript\{($nobrackets)\}/ startsubscript $1 endsubscript/g;
s/\\textit\{($nobrackets)\}/ startitalic $1 enditalic/g;  
s/\\textcolor\{$nobrackets\}//g;
s/\{($nobrackets)\}/($1)/g;
 print "Pass $pass:\n\n". qq{$_}."\n\n\n";
}