TOPIC: Don't have the write comment phrase

Hi
I have a blog in my website and when i instaled the joomlacomment i don't had the write a comment option. Insted i have the fields ready for write the comment.
I want the phrase write a comment if the user wants to. What i'm doing wrong?
Please see the problem at
www.mariolopes.com/index.php?option=com_...ction&id=4&Itemid=16
(portuguese language, please select blog and one of titles)
Thank you
mario

The write comment phrase doesn't show in single view(article view) it shows in section, category, blog or frontpage view.