=head2 More reading
-If you have difficulties with the way I try to explain them please read
+If you have difficulties with the way I try to explain it please read
Steve Rader's L<rpntutorial>. It may help you understand how this all works.
=head1 What are CDEFs ?
Most people will use the counter that keeps track
of octets (bytes) transfered by a network device so we have to do just
that. We will start with a description of how to collect data.
-Some people will make a remark that there are tools who can do this data
+Some people will make a remark that there are tools that can do this data
collection for you. They are right! However, I feel it is important that
you understand they are not necessary. When you have to determine why
things went wrong you need to know how they work.