The exercise does not say what needs to be done with a line that ends in a period, question mark comma, but does not contain the word "it". So, I assume this program runs in a universe that does not have such lines. So, I'd write (untested): 
perl -nlwe 'print $1 if /\bit\b(.*[.?,])$/' text-file

[download]
Or: 
perl -nlwe '/[.?,]$/ && /\bit\b/ && print $'"'" text-file

[download]

In reply to Re: Lost in Perl - text file searching and printing by JavaFan
in thread Lost in Perl - text file searching and printing by slygon

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