How do I delete what I pasted (even images are pasted) from this article?

I pasted it into my Gmail. I was just testing it because the highlighting was in yellow as opposed to the usual blue. I didn’t intentionally hightlight the whole page. It highlighted the whole page images included. But when I tried to delete it it refused. What happens when you try it?
http://www.slate.com/articles/double_x/doublex/2013/10/sexual_assault_and_drinking_teach_women_the_connection.html