i can't write english well.sorry for it

i create several content ... for example i posted 4 content with "energy of drink" title and same content...xmlsitemap is installed on my site.you know that duplicate content is bad for google,pathauto change urls for prevention of duplicate urls.
every 4 content that i have posted to site will be index at google.
1- is duplicate content bad for google ranking? (no duplicate address,duplicated content)
2- if i select the "exclude" option from combobox in "inclusion" part (this fieldset added by xmlsitemap to node/add pages.) what happened?