Barnes & Noble NOOK User Manual page 40

Changing the Selection from a Word to a Passage
To select an entire passage, rather than just a word, select the word that you want to have at the beginning or the end
of the selected page and drag the vertical bar that's closest to the direction in which you want to extend the passage.
Drag the vertical bar until you have selected the passage you want.
Select a word at the beginning or the end of the passage you want to select, and extend the selection by dragging a vertical bar.
When you lift your fingers after resizing the text selection, the Text Selection Toolbar re-appears.
40 Barnes & Noble NOOK User Guide