Apostrophes can be used in a couple of ways. With contractions, use apostrophes to indicate that letters are missing. When two words are written in shortened form, use an apostrophe to show that some ...

Those of us who respect and appreciate proper apostrophe usage awoke yesterday to some upsetting news: John Richards, one of the most ardent defenders of the correct use of the apostrophe, is giving ...

If it's a singular noun, the apostrophe goes before the 's'. It doesn't matter if thing or person owned is singular or plural The boy's shirt = one owner, the boy The doctor's patients = one owner, ...