my @wordarray = split /\s+/, $sentence; 
 chomp foreach(@wordarray);
 @wordarray = grep {length} @wordarray; 
	    
 for(my $wordindex=0; $wordindex <= $#wordarray; $wordindex ++){
		
	my $word1 = $wordarray[$wordindex]; 
	while ($word1 =~ /(.*?)\/([A-Z]+)/g){
		$valueword1 = $1;
		$keyword1 = $2;
	}
	my $word2 = $wordarray[$wordindex+1]; 
	while ($word2 =~ /(.*?)\/([A-Z]+)/g){
		$valueword2 = $1;
		$keyword2 = $2;
	 }

	$patternKey = join("/",$keyword1, $keyword2);
	$patternValue = join(" ",$valueword1, $valueword2);

	print "key $patternKey \n";
        print "value $patternValue \n";
        my $matchingKey = grep($patternKey, @PatternArray);
        ...