The apostrophe ( ' )is used to
a) indicate nouns and indefinite pronouns which show ownership.
's is added to nouns and indefinite pronouns unless they already end in -s. In this case, only the apostrophe is added after the final -s.
Tom's wallet was stolen.
The children's toys were colorful.
Everyone's job was to clean the kitchen.
The boys' cat finally came home.
James' dinner was cold.
Note: Possessive personal pronouns (his, hers, its, ours, yours, theirs) do not contain apostrophes.
b) indicate individual ownership for words in a series; to indicate joint ownership for words in a series.
Individual Ownership: Tim's and Chris' books were left on the table.
Joint Ownership: Tim and Chris' book was left on the table.
c) indicate a contraction by replacing the omitted letters or numbers.
did not = didn't
they are = they're
of the clock = o'clock
madam = ma'am
I will = I'll
Class of 1971 = Class of '71
d) form plurals of a letter, numeral, or words considered as one word. The letters, numerals, and words – but not the apostrophe and s – are italicized.
Watch your p's and q's.
His 5's resemble his 8's.
I haven't written my thank you's yet.
|Abbreviations with periods are not italicized.
||Johanna and Steven received their Ph.D's.
|Abbreviations and acronyms without periods
do not contain the apostrophe in the plural form.
||We have two VCRs in our house.
My brother found my IOUs in his wallet.
|Decades do not include an apostrophe.
||The 1960s were a tumultuous ten years.
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