my $phrase;
foreach $phrase (@key_phrases) {
     my($worda,$wordb) = split(/ /, $phrase);
     foreach (@material) {
          last if
          (s|([\W\b])($worda)(\W+)($wordb)([\W\b])|
               $1<B>$2</B>$3<B>$4</B>$5|i);
     }
}

# Here's where I clean up redundant tags...
foreach (@material) {
     s|<B><B>|<B>|g;
     s|</B></B>|</B>|g;
     s|</B> <B>| |g;
}