IMHO using hashes like this is a bad idea, because different $2 for the same $1 will be lost.

Furthermore looking for non-whitespace and non-punctuation could help practically solving the "what is a word problem".

 my %hash;

$whitespace=" \n\t";
$punctuation=".,!?";
$non_delimiters="[^$whitespace$punctuation]";


while (<DATA>) {
  push @{$hash{$1}}, $2 while m/($non_delimiters+)\s+going\s+($non_del
+imiters+)/g;
}

use Data::Dumper;
print Dumper \%hash;

__DATA__
I am going home.
I am going to bed.
What's going on?
[download]

Output:

$VAR1 = {
          'What\'s' => [
                         'on'
                       ],
          'am' => [
                    'home',
                    'to'
                  ]
        };
[download]

I'm still not sure if a hash should be used at all, IMHO an array of pairs (two elemnet arrays) is better.