Punctuation
Apostrophe

Apostrophe

The apostrophe is used primarily to show ownership, but it is also used to form a contraction.

This is Johns cap.
This is the boys cap.

The problem for most students is whether to place the apostrophe before or after the letter s. For example, should they write the boys cap or the boys cap?

To determine whether the apostrophe should be placed before or after the s, change the sentence structure so that there is no apostrophe. In this case, you would write the cap belonging to the boy. Since there is only one boy, the apostrophe is placed before the s.

However, the apostrophe will go after the letter s if the possessive is showing the plural case. For example, if a group of teenagers pooled their money and purchased a motorcycle among them, then the motorcycle belongs to all of them. Thus you would show ownership by writing the boys motorcycle, because the motorcycle belongs to all the boys, not just one boy.

You may have to depend on the context (other information in the sentence or the paragraph) to determine ownership.

You can use the context in the following sentences to determine ownership and thus the correct placement of the apostrophe to show ownership.

The boy saved his money and purchased a motorcycle, so it is the boys motorcycle.

The boys pooled their money and purchased a motorcycle, so it is the boys motorcycle.

Note: The apostrophe is never used to make a word plural.

 The boys prepared for their weekend of canoeing and kayaking.
 The boys prepared for their weekend of canoeing and kayaking.

Contraction

A contraction is a word that is shortened by using an apostrophe to replace the letter or letters that are omitted.

For example, the word cant is a contraction for the word cannot.

A contraction always requires an apostrophe.

  Shouldnt the winner of the high school speaking contest be given a prize?
  Shouldnt the winner of the high school speaking contest be given a prize?

Letters and numbers

To avoid possible confusion, use an apostrophe and an s to show the plural form of lowercase letters.

 Mother always reminded us to watch our ps and qs.
 Mother always reminded us to watch our ps and qs.

However, this rule does not apply to numbers or uppercase letters.

 The student got four 50s on his midterm exams, which are equivalent to four Ds.
 The student got four 50s on his midterm exams, which are equivalent to four Ds.

 The student attended university in the early 1990s.
 The student attended university in the early 1990s.

Compound possessive

A compound possessive is made up of more than one word, for example, son-in-law.

Possession is shown by placing an apostrophe and an s after the last word.

 The woman sent the invitation to her daughter-in-laws address.

To form the plural of a compound possessive, the s is added after the first word, and no apostrophe is required.

 The woman was proud to have two daughters-in-law.

The possessive of a plural compound is still formed by adding the apostrophe and an s after the last word.

 The woman sent the invitations to her daughters-in-laws addresses.

Joint and separate possession

A car belongs to Peter and Hannah, so they have joint ownership.

 Peter and Hannahs car was towed to the garage.

One apostrophe indicates joint ownership, so the apostrophe and the s are placed after the last name.

Peter and Hannah both own a car, so there is individual ownership.

 Peters and Hannahs cars were ticketed because they were illegally parked.

Two apostrophes indicate separate ownership, so the apostrophes are placed after each name.

Practice

Choose the correct answer for each of the two practice sentences below by clicking on the correct answer.

(1) The (dog's, dogs') paw was injured when it stepped on some broken glass.

(2) The (dog's, dogs') paws were injured when they stepped on some broken glass.


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