Apostrophes

Apostrophes
Lesson & Exercises

Singular Plural (-s, -es) Singular Possessive (-’s) Plural Possessive (-s’)

Bird Birds Bird’s Birds’

Business Businesses Business’s Businesses’

To form the plural of a regular noun, add –s. When a singular noun ends in –s, add –es. Do not add an apostrophe.

Correct: The birds are flying. = More than one bird is flying.

Correct: The businesses are open today. = More than one business is open today.

Correct: The Wangs are home this evening. = The Wang family is home this evening.

To form the possessive of a singular noun, add apostrophe + –s, even for nouns whose singular form ends in –s.

Correct: The bird’s wings are red. = The wings of the bird are red.

Correct: The business’s policy is new. = The policy of the business is new.

In general, this rule also applies to names, including ones that end in –s.

Correct: Mrs. Wang’s coat = The coat belonging to Mrs. Wang

Correct: Alice’s backpack = The backpack belonging to Alice

Correct: Douglas’s cup of coffee = The cup of coffee belonging to Douglas

Note that in the case of well-known historical or literary figures whose names end in –s, it is acceptable to use an
apostrophe alone. This exception accounts for much of the confusion surrounding apostrophes.

Correct: Dickens’ novels = The novels written by Dickens

Correct: Moses’ staff = The staff belonging to Moses

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To form the possessive of a plural noun, add –s or –es + apostrophe. Note that while the apostrophe comes before
the –s when making singular nouns possessive, it comes after the –s when making plural nouns possessive.

Correct: The birds’ wings are red. = The wings of the birds are red.

Correct: The businesses’ policies are new = The policies of the business are new.

Correct: The Wangs’ house is blue. = The house belonging to the Wangs is blue.

The plural forms of irregular nouns are not created by adding –s to their singular forms. Instead, these nouns
change in a variety of ways in the plural forms. Some common examples are listed below.

Singular Plural
Child Children
Fish Fish
Foot Feet
Mouse Mice
Person People
(Wo)man (Wo)men

To form the possessive of a singular irregular noun, add apostrophe + –s, just as you would for a regular noun.

Correct: The mouse’s whiskers = The whiskers of the mouse

Correct: The child’s books = The books belonging to the child

To form the possessive of a plural irregular noun, also add apostrophe + –s.

Correct: The mice’s whiskers = The whiskers of the mice

Correct: The children’s books = The books belonging to the children

Note that because these plural forms are already different from their singular forms, the fact that both singular and
plural possessive are formed by adding apostrophe + –s does not cause confusion.

As a general rule, you can determine whether a noun should be possessive by checking the word after it. If that
word is a noun, the noun is possessive and should take an apostrophe. If you think about it, this is entirely logical:
the only thing a noun can possess is another noun.

Incorrect: The dogs fur is gray.

Because fur is a noun – that is, you can put the in front of it – an apostrophe is needed.

Correct: The dog’s fur is gray.

Contraction with Verb

Apostrophe + –s is also used to form a contraction between a noun and the verb is or has.

Correct: The artist’s known for her abstract sculptures. = The artist is known for her abstract sculptures.

Correct: The reporter’s worked all over the world. = The reporter has worked all over the world.

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 Pronouns
A pronoun is a word such as it(s), s/he, they/their, or which that can replace a noun in a sentence. For example, the
sentence I.M. Pei is a well-known architect can be re-written as He is a well-known architect.

The most important thing to understand is that apostrophes and –s are used differently for pronouns than for
nouns. The addition of –s alone is only related to whether a pronoun is possessive; it has nothing to do with
whether a pronoun is plural.

• To form the possessive of a pronoun, add –s. Do not add an apostrophe.

• To form a contraction with a verb, add apostrophe + –s (is), –re (are), –d (would), –m (am), or –ve (have).

Again, you can determine whether a pronoun is possessive by checking the word after it. If that word is a noun, the
pronoun is possessive (no apostrophe).

A. It’s vs. Its

It’s = it is, it has

Its = possessive of it. Used before a noun.

Its’ & Its’s = do not exist

The easiest way to choose between its and it’s is simply to plug in it is. If it is makes sense in context, an apostrophe
is needed. If it is does not make sense, the apostrophe is incorrect. Alternately, you can check whether the word
after the pronoun is a noun.

Incorrect: Some critics of the Internet have argued that it is a danger because it’s (it is)
vastness threatens people’s intellectual health.

Incorrect: Some critics of the Internet have argued that it is a danger because its’ vastness
threatens people’s intellectual health.

Correct: Some critics of the Internet have argued that it is a danger because its vastness
threatens people’s intellectual health.

Because you would not say, it is a danger because it is vastness threatens people’s intellectual health, no apostrophe
should be used. In addition, the word after its is a noun, as indicated by the ending –ness.

B. They’re, Their, and There

Although the same rules apply to they’re vs. their as apply to other pronouns, an extra degree of confusion is often
present because of a third identical-sounding pronoun: there.

They’re = they are

Their = possessive of they. Used before a noun.

There = a place

In general, it’s easiest to think of there as separate from they’re and their, which both involve they. To check their vs.
they’re, plug in they are. If it makes sense, the apostrophe is needed; if it doesn’t, no apostrophe should be used.

To check there, simply ask yourself whether the pronoun is referring to a place. The context provided by a sentence
or paragraph will make it clear whether this is the case.

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They’re

Incorrect: Although their usually powered by rowers, canoes may also have sails or motors.

Incorrect: Although there usually powered by rowers, canoes may also have sails or motors.

Correct: Although they’re usually powered by rowers, canoes may also contain sails or
motors.

Because you would say, Although they are usually powered by rowers, the apostrophe is required.

Their

Incorrect: Deactivated viruses form the basis of many vaccines known for they’re effectiveness
in preventing disease.

Incorrect: Deactivated viruses form the basis of many vaccines known for there effectiveness
in preventing disease.

Correct: Deactivated viruses form the basis of many vaccines known for their effectiveness
in preventing disease.

Because you would not say, Deactivated viruses form the basis of many vaccines known for they are effectiveness, no
apostrophe is needed. The sentence does not describe a place, so there is not correct either.

There

Incorrect: Because Denver is located close to the Rocky Mountains, snow often falls they’re.

Incorrect: Because Denver is located close to the Rocky Mountains, snow often falls their.

Correct: Because Denver is located close to the Rocky Mountains, snow often falls there.

Because the sentence is clearly talking about a place, there is required.

C. Who’s vs. Whose

Who’s = who is, who has

Whose = possessive form of who. Note that unlike who, whose can refer to both people and things.

To determine which version is correct, plug in who is.

Incorrect: Jessye Norman is an American opera singer whose known for her moving
performances.

Correct: Jessye Norman is an American opera singer who’s known for her moving
performances.

Because you would say, Jessye Norman is an American opera singer who is known for her moving performances, the
apostrophe is necessary.

In addition, the pronoun is followed by a verb (known) rather than a noun, indicating that the possessive should not
be used.

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On the other hand:

Incorrect: Jessye Norman is an American opera singer who’s performances many people
find moving.

Correct: Jessye Norman is an American opera singer whose performances many people
find moving.

Because you would also not say Jessye Norman is an American opera singer who is performances many people find moving,
whose is correct.

In addition, the pronoun is followed by a noun (performances), indicating that the possessive form is required.

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The same rule applies to the pronouns below as applies to the ones discussed in the previous pages.

• Apostrophe + –s, –re, –d, or –ve = contraction with verb

• No apostrophe = possessive.

Pronoun + verb Possessive Incorrect

I I’m -- Im

You You’re, You’ve, You’d Your(s) Your’s, Yours’

He, She S/he’s, S/he’d His, Her(s) His’, Her’s, Hers’

We We’re, We’ve, We’d Our(s) Our’s, Ours’

That That’s -- Thats, Thats’

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Exercise: Possessive vs. Plural
For the following exercises, write the correct form of the underlined noun or pronoun in the space provided.
Some of the underlined words may already be in the correct form.

1. For years, seismologists have been trying to identify

___________________________
microquakes, earthquakes so tiny that they’re waves don’t even
register on traditional measurement tools.

___________________________
2. Fiction allows readers to understand other peoples’ action’s by
entering into characters’ minds and seeing situations from their ___________________________
interior points of view.

3. The architect Renzo Piano earned a reputation as an innovator

___________________________
for his design of Paris’s Pompidou Center, who’s exterior consists of
brightly colored tubes.

4. Chunks of ice and dust, which make there home in corners of ___________________________
the galaxy far beyond Pluto, sometimes become dislodged and enter
___________________________
the solar system as streaky comet’s.

5. Recognized today as one of the worlds’ leading authorities on ___________________________

the Sphinx, archaeologist Mark Lehner has conducted field research
on the pyramids at Giza for nearly four decades.

___________________________
6. Like today’s astronauts, future space colonists are likely to be
selected on the basis of they’re suitability for long-duration
spaceflight. ___________________________

7. Circadian rhythms dictate many of the bodies most ___________________________

fundamental process’s, including eating, sleeping and hormone
___________________________
production.

8. Its not yet clear how much plastic is consumed by corals in the
___________________________
wild, or what harm it might do to these important marine
organisms, whose lives are already threatened by environmental
___________________________
dangers like warming seas and pollution.

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9. The planet Venus is believed to have contained Earth-like ___________________________
oceans at some point in its’ history, but these bodies of water
___________________________
evaporated as temperatures rose.

___________________________
10. Brought back from the brink of extinction, the South American
vicuna, a llama-like animal, has attracted the attention of poacher’s
eager to profit from it’s prized wool. ___________________________

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Answers: Possessive vs. Plural

1. For years, seismologists have been trying to identify

microquakes, earthquakes so tiny that their waves don’t even
register on traditional measurement tools.

2. Fiction allows readers to understand other people’s actions by

entering into characters’ (correct) minds and seeing situations from
their interior points of view.

3. The architect Renzo Piano earned a reputation as an innovator

for his design of Paris’s Pompidou Center, whose exterior consists of
brightly colored tubes.

4. Chunks of ice and dust, which make their home in corners of

the galaxy far beyond Pluto, sometimes become dislodged and enter
the solar system as streaky comets.

5. Recognized today as one of the world’s leading authorities on

the Sphinx, archaeologist Mark Lehner has conducted field research
on the pyramids at Giza for nearly four decades.

6. Like today’s (correct) astronauts, future space colonists are

likely to be selected on the basis of their suitability for long-duration
spaceflight.

7. Circadian rhythms dictate many of the body’s most

fundamental processes, including eating, sleeping and hormone
production.

8. It’s not yet clear how much plastic is consumed by corals in the
wild, or what harm it might do to these important marine
organisms, whose (correct) lives are already threatened by
environmental dangers like warming seas and pollution.

9. The planet Venus is believed to have contained Earth-like

oceans at some point in its history, but these bodies (correct) of
water evaporated as temperatures rose.

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10. Brought back from the brink of extinction, the South American
vicuna, a llama-like animal, has attracted the attention of poachers
eager to profit from its prized wool.

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