I go through this every year in mid-February: looking through the ads for refrigerators, mattresses and windows, I see three different ways to show why Washington and Lincoln were born to sell these items. Which one is correct?
That’s a shadow,. This banner has no apostrophe.
And here is only one president—but is it Washington or Lincoln selling you windows?
Obviously, the correct punctuation is seen in the second example. The rule for using apostrophes is very simple: take the owner word and add ‘S. If the owner word happens to end in an S, just add an apostrophe (boss=boss’).