OF and ‘S, the Genitive Case

A common mistake I see with English language learners is the incorrect use of the apostrophe + s, “-‘s” in the genitive case. Although we natives of English use it rampantly, there are moments when it simply cannot be applied. And it is in these moments that I hear my students make mistakes.

Here’s a typical example of how an English learner uses the genitive case incorrectly: the food’s price, the curtain’s color, the book’s title, etc. To the chagrin of the English teacher, the student’s habit of using it this way becomes one quite difficult to break.

There’s much more to this case than meets the eye! Here are a few simple rules to follow:

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Clique aqui e acesse!

We normally use -‘s for people, animals, or places:

  • Liz’s computer isn’t working.
  • Those aren’t my sneakers. They’re my sister’s.
  • The dog’s food bowl is empty.
  • New York City’s crime rate is at an all time low.

You can use -‘s with time expressions and periods of time:

  • Have you seen the headline on the front page of today’s newspaper?
  • Santa Barbara is about an hour’s drive from Los Angeles.

Remember that for plural nouns we use s + apostrophe, -s’:

  • My brothers’ wives are very nice. (two or more brothers)
  • The cats’ toys are in the box. (two or more cats)
  • I have three months’ vacation.

For things, ideas etc., we normally use of:

  • The price of a university education in The U.S. is extremely high. (NOT the university education’s price)
  • The color of his shirt is the same as his shoes. (NOT the shirt’s color)
  • The source of her depression comes from a failing marriage. (NOT her depression’s source)

We also say the beginning/middle/end of; the top/bottom of; the front/back/side of:

  • I was in the middle of cleaning my house when you called.
  • Jim’s house is at the top of the hill.
  • Did you see the coat hanger on the back of the door?

Both -‘s and of can be used for an organization:

  • The company’s failure was due to overspending. (OR the failure of the company)
  • It was the decision of the university Council to fire the professor. (OR the Council’s decision)

Entendeu diretinho? Agora jamais vai esquecer como usar o genitive case em inglês!

Até o próximo artigo!

Há quanto tempo você estuda inglês? Já passou por sua cabeça que você pode estar estudando de uma forma que dá pouco ou quase nenhum resultado? Que tal fazer um intensivo de inglês de 180 dias e recuperar o tempo perdido? Em 6 meses você pode elevar o seu inglês a um novo nível. Clique aqui e saiba como.


Ashley Smith

Ashley Smith é americana que mora no Brasil desde 2001. Durante os primeiros sete anos aqui ela dava aulas particulares de inglês, e atualmente trabalha como diretora de conteúdo do site meuingles.com.

28 comentários

  • 24/05/09  
    Ronniere Larry diz: 1

    O My God, that’s helped me alot. My knownledges got greatly ehanced after that. Thank you so much.

  • 25/05/09  
    Thaís diz: 2

    And how would i be to write “O livro da Thaís” since Thaís ends with an “s”? Would it be “Thaís’ book”?

  • 25/05/09  
    Ashley Smith diz: 3

    I’m glad I was able to help, Ronniere Larry!

  • 25/05/09  
    Nuclear Winter diz: 4

    Great post. :)

  • 25/05/09  
    Ashley Smith diz: 5

    Thaís, you would write it as “Tais’s book”. Mesmo quando um nome termina com “s” você adiciona outro “s”.

  • 25/05/09  
    Jefferson Alves diz: 6

    Perfect post, I love, helped me very, very really. I don’t imagine that.

    Thanks *-*

  • 25/05/09  
    Josie diz: 7

    Awesome! Nunca na história do meu aprendizado em Ingles os professores explicaram dessa forma…rsrsr… Great explanation!

  • 25/05/09  
    Karina diz: 8

    seria bom se esse texto fosse traduzido p/ o português, pois eu ainda não tenho muita noção de inglês!
    genetive cases sempre me confunde

  • 26/05/09  
    Mary diz: 9

    Do you think it sounds wrong to say, “the book’s title is too short?”

    And “What is ironic about the book’s title?”

  • 26/05/09  
    Ashley Smith diz: 10

    Hi Mary, yes, it does sound very strange to say “the book’s title”. I don’t think you would hear a native speaker of English saying this. In fact, if you were to “google” “book’s title” you would see that it says “você quis dizer the book title”. The book title is ok, the title of the book is more common, but the book’s title, no. Think of it this way, a book is an inanimate object, so it cannot possess anything. Does that help?

  • 27/05/09  
    Eri diz: 11

    Great blog! Great tips, Ashley.
    Thanks a lot! I will come back here everyday.

  • 27/05/09  
    leandro diz: 12

    Very good !


  • 28/05/09  
    Rafaella diz: 13

    Tenho um ENORME problema em usar o ´s, mas agora entendi o porque dos meu erros. meus antigos professores sempre me ensinaram que o ´S SEMPRE significava of, então a frase:

    – The price of a university education in The U.S. is extremely high. poderia ser usado perfeitamente o education´s price porque era o “price of education”

    então tudo que era … of “alguma coisa” eu tentava usar o ‘S

  • 29/05/09  
    Ashley Smith diz: 14

    Que bom que esse blog clarificou o genitive case para você, Rafaella! É por isso que eu fiz.

  • 29/05/09  
    Mary diz: 15

    Thanks Ashley. To me, it sounds ok in the sentences that I submitted. I view it as a parallel construction to “the book’s pages are dog-eared,” the book’s height is 8 inches, The book’s cover is torn, the book’s binding is in need of repair.”

    http://www.bartleby.com/68/26/5226.html says the following about possessives: “The possessive or genitive case in nouns adds apostrophe (’) plus s in the singular, s plus apostrophe in the plural. The pronunciations are not always as distinctive as the spellings: boys, boy’s bike, boys’ bikes; dresses, this dress’s skirt, these dresses’ skirts.”

  • 29/05/09  
    Mary diz: 16

    In addition, I found this example: “Singular possessive
    The possessive form of a singular noun is an apostrophe followed by the letter “s.”

    Kramer’s hair
    Daphne’s patience
    the car’s engine” at http://www.meredith.edu/grammar/plural.htm#and%20x .

    Both ‘car’ and ‘dress’ in the examples from Strunk’s style manual and the grammar page which cites (Bedford 36a/Hodges’ 15a) confirm the use of ‘s after inanimate nouns to show possession.

  • 29/05/09  
    Mary diz: 17

    It can be correctly used to differentiate between two items or specify which object is meant. http://forum.wordreference.com/showthread.php?t=235314 said, “When you use “the door’s handle” it’s used to emphasize that the relation between the door and the handle or after you have introduced the door by itself previously. For example:

    The door was on the left side of the room. The door’s handle was red.”

    Compare: The door’s handle is read, but the drawers’ handles are yellow.

  • 29/05/09  
    Mary diz: 18

    http://forum.wordreference.com/showthread.php?t=235314 further explains:

    “When speaking of the type of handle used for a door, you would say the door handle. But the door’s handle could be used when speaking of a particular door–that is, when the with the emphasis on the door itself–as in, Not only did it need to be stripped and repainted, but the door’s handle was rusty.

    It’s not appropriate to refer to the door as an “owner” of the handle, as you imply in your message. The term possessive case is thus misleading: Using the term genitive case instead helps one to avoid the myth that the marker ‘s cannot be used with inanimate objects. As Kenneth G. Wilson points out, in his Columbia Guide to Standard American English under the article Descriptive Genitive, “In fact, the genitive case–in English as in Latin before it–has always had many more purposes than simply indicating possession, and descriptive (and other nonpossessive) genitives are and long have been Standard English.” Wilson gives as examples of the descriptive genitive the mountain’s top and a day’s pay.”

  • 14/06/09  
    vicente diz: 19

    como dizer “na gaiola da dor” em inglês?

  • 22/06/09  
    Ale Santiago diz: 20

    Thank you very much! Really helpful!

  • 24/07/09  
    Neli diz: 21

    Ixi… estou tentando aprender inglês sozinha, sou iniciante. Como posso ler um artigo em Inglês???

  • 06/08/09  
    Rafael Nogueira diz: 22


    That’s a grammar rule I was in doubt.

  • 03/02/10  
    Amanda diz: 23

    Help me…
    fica errado colocar assim:
    “I am Johnny’s fan”
    ou o certo seria:
    “I am fan of Johnny”


    • 03/02/10  
      Alessandro diz:


      Com relação ao genitive case ambas estão corretas. Porém na primeira eu colocaria o artigo “a” antes de “Johnny”. Ficaria assim “I am a Johnny’s fan”.

      Bons estudos

  • 13/05/10  
    Robson diz: 24

    I would like to know if I need to use S after apostrophe in these cases, or is the same rule of plural ending in S.

    My boss’s car/ My boss’ car.
    The waitress’s job/ The waitress’ job.

    • 13/05/10  
      Alessandro diz:


      You can omit apostrophe S in these cases.

      See you!

  • 22/05/10  
    Robson diz: 25

    So, the sentense: “My boss car” is correct? Shouldn’t I use at least an apostrophe? Like: My boss’ car.

    Thanks! See you!

  • 22/12/16  
    George Tower diz: 26

    If the onwer of the car is my boss, I shall write ‘My boss’s car’. But, if the car is of the same style or make of my boss, I shall write ‘My boss car’. In my eyes, they both have different meanings or ideas.