# setup the parser to capture the contents of all <li> chunks into @array, then

foreach ( @array ) {
    if ( m{(.*?)<pre>(.*)</pre>}s  # NB: "?" makes ".*" non-greedy
         or /(.*\?)\s+(\S.*)/s     # NB: "\?" matches a literal qmark 
         or /^([^.]+)\.\s+([^.]+\.)\s*$/s ) {
        push @questions, $1;
        push @answers, $2;
    }
    else {
        # you have a harder case to solve (might need a human)
    }
}