Apostrophes have two uses on the ACT and SAT:
1. To form possessive nouns.
2. To replace missing letters in contractions.
Let’s examine these two situations–as well as when to avoid apostrophes–in this week’s blog.
Nouns that show ownership must use an apostrophe:
Karla’s pen, the cat’s tail, somebody’s idea, the Wilsons’ house
The rules for apostrophes and possessive nouns are as follows:
A. A singular noun receives an apostrophe + s (’s)
Dan’s letter, the lawyer’s argument, a car’s interior
Note that this is true even if the noun ends in -s:
Carlos’s soda, Mr. Williams’s classroom, the dress’s seam
B. A plural noun that does not end in -s receives an apostrophe + s (’s)
The children’s toys, the men’s club, the people’s politician, the oxen’s harnesses
C. A plural noun that ends in -s receives just an apostrophe (’)
The two dogs’ collars, the ladies’ luncheon, the Smiths’ vacation
Avoid apostrophes with possessive pronouns. There are seven possessive pronouns that have been known to incorrectly use an apostrophe on the ACT and SAT:
yours his hers its ours theirs whose
Consider some examples:
Incorrect: The orange tree is not your’s; it’s their’s.
Correct: The orange tree is not yours; it’s theirs.
Incorrect: The dog refused to walk on it’s front leg after I accidentally stepped on it.
Correct: The dog refused to walk on its front leg after I accidentally stepped on it.
Apostrophes are also used to show that letters have been removed from words:
Note that the apostrophe is always located where the omitted letters originally stood.
If you come across a contraction, test it by using the original phrasing:
Incorrect: Susie, who’s last day at work is tomorrow, is moving to Abu Dhabi. Although I’m prepared for her departure, it’s still hard to see her leave.
Test: Susie, who is last day at work is tomorrow, is moving to Abu Dhabi. Although I am prepared for her departure, it is still hard to see her leave.
Correct: Susie, whose last day at work is tomorrow, is moving to Abu Dhabi. Although I’m prepared for her departure, it’s still hard to see her leave.
It’s clear that who is is incorrect in the test sentence. Since the last day belongs to Susie, the possessive pronoun whose belongs in place of the contraction. The other two contractions are correct. You should test possessive pronouns in a similar manner to make sure that a contraction is not warranted instead.