Apostrophes

An apostrophe [ ’ ] is used to create possessive forms, contractions, and some plurals. The apostrophe shows where a letter or letters have been left out of a contracted verb:

• I am = I'm
• you are = you're
• she is = she's
• it is = it's
• do not = don't
• she would = she'd
• he would have = he would've
• let us = let's
• who is = who's
• she will = she'll
• they had = they'd
  

In possessives, the placement of the apostrophe depends on whether the noun that shows possession is singular or plural. Generally, if the noun is singular, the apostrophe goes before the s.

• The witch's broom.

If the noun is plural, the apostrophe goes after the s: The witches' brooms. However, if the word is pluralized without an s, the apostrophe comes before the s: He entered the men's room with an armload of children's clothing. If you create a possessive with a phrase like the witches, you will use no apostrophe:

• the brooms of the witches.

Remember that it's means it is or it has. Confusing it's with its, the possessive of it, is one of the most common errors in writing. Remember, too, that there is no appropriate contraction for "there are." Don't confuse "they're," which means "they are" with "there are".

An apostrophe is also used to form some plurals, especially the plural of letters and digits. Raoul got four A's last term and his sister got four 6's in the ice-skating competition. This is particularly useful when the letter being pluralized is in the lower case:

• minding one's p's and q's.

or

• Don't forget to dot your i's.
  

In a context in which the plural is clear, apostrophes after upper-case letters are not necessary:

• He got four As, two Bs, and three Cs.
  

It is no longer considered necessary or even correct to create the plural of years or decades or abbreviations with an apostrophe:

• He wrote several novels during the 1930s.
• There are fifteen PhDs on our faculty.
• My sister and I have identical IQs.
  

Acronyms

If the abbreviation or acronym ends in "S," it's a good idea to separate this final "S" from the pluralizing "s" with an apostrophe:

SOS's