You mean something like this?

my $str = "It/PRP really/RB does/VBZ seem/VB to/TO violate/VB a/DT lot
+/NN of/IN boundaries!/NNS";

my @pairs = map { [ m!(\w+).*?/(\w+)! ] } split /\s+/, $str;

for (0..$#pairs-1) {
    print $pairs[$_][0], " ", $pairs[$_+1][0], "\n";
}
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To handle non-consecutive pairs of words:

$nth = 2; # every 2nd words
for (0..$#pairs-$nth) {
    print $pairs[$_][0], " ", $pairs[$_+$nth][0], "\n";
}
[download]