Problem Highlighting More Than One Word on NOOK Tablet

[NotYingYang]

Hi there - I am currently reading a book on my NOOK Tablet, and I can't seem to highlight more than one word in the ebook. I long-press and then try dragging, but what that does is simply highlight individual words under where my finger is instead of the whole sentence. How do I highlight more than one word? I appreciate any help!