Most likely, you'll rather want to write "1 comment" than "1 comment(s)". The "One comment" and "Many comments" template parts can be used for this purpose. They will be used to fill the <%commentword%> variable that you can use elsewhere.

If there is only 1 comment, <%commentword%> will be equal to the contents of the "one comment" part. If there are many comments (more than one), <%commentword%> will be equal to the contents of the "two (or more) comments" part.

Typical values are "comment" and "comments". No special variables can be used here.