Condition to Find whether “more quick tag” is present in a post

Dear all,

In the home page, i have a list of posts. If the post is small, I am display the whole post and if the post is large, i break it with “more tag” and display only a part of it.

I want to change the more text different in both the cases. If the whole post is displayed, i need the more text to be “Comment on this”.

If only a part of the post is displayed, I need the more text to be “Read more and comment on this”.

Please please some one help me..

Thank you!
Dave