… The ellipsis (plural ellipses), or three dots in a row, tells the reader that words have been omitted from a quotation.  When used at the end of a sentence, add a fourth dot to show a period as the ending punctuation.  Ellipses can also indicate that the writer’s thoughts are unfinished or have trailed off; in this way, it should be used sparingly.

Example:

I knew I could convince Adrian to work more hours at the factory; I also knew I would pay a price(an unfinished thought)

(Quotes below are from A Tree Grows in Brooklyn by Betty Smith (a great book, by the way!)

“Francie turned and went down into the cellarwaiting until the waves of hurt stopped breaking over her.”

“Gradually, as the children grew up, Katie lost all of her tenderness….

Christa Riddle, All About Writing, Howell, NJ, www.allaboutwritingconsulting.com