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Accueil English Grammar Unit 81 — -'s and of
Unit 81 · Grammar Lesson
Unité 81 · Leçon de Grammaire

-'s (your sister's name) and of…
Possessive apostrophe · of for things · time expressions — Complete Guide
-'s (your sister's name) et of…
Apostrophe possessif · of pour les choses · expressions de temps — Guide Complet

Master when to use -'s (for people, animals, time words, places) vs of… (for things and ideas), including tricky cases like singular vs plural apostrophe and organisational possession.

Maîtrisez quand utiliser -'s (personnes, animaux, mots de temps, lieux) vs of… (choses et idées), y compris les cas difficiles comme le singulier/pluriel et la possession organisationnelle.

B1 – B2 5 Rules · 4 Exercises · 200-Q Quiz · PDF 5 Règles · 4 Exercices · Quiz 200 Q · PDF 🇬🇧 EN / 🇫🇷 FR

In English, possession can be expressed in two main ways: -'s (apostrophe + s) or of…. The choice depends on whether the "owner" is a person/animal, a thing/idea, an organisation, a place, or a time reference. Getting this right is essential for natural, accurate English.

En anglais, la possession peut être exprimée de deux façons principales : -'s (apostrophe + s) ou of…. Le choix dépend de si le « possesseur » est une personne/animal, une chose/idée, une organisation, un lieu ou une référence temporelle. Maîtriser cela est essentiel pour un anglais naturel et précis.

A

-'s for People and Animals

-'s pour les Personnes et les Animaux

We use -'s (apostrophe + s) mostly for people or animals. We can also use -'s without a noun after it when the noun is understood. We do not use -'s after a long group of words.

On utilise -'s (apostrophe + s) principalement pour les personnes ou les animaux. On peut aussi utiliser -'s sans nom après quand le nom est sous-entendu. On n'utilise pas -'s après un long groupe de mots.

✓ Tom's computer isn't working. (not the computer of Tom)
How old are Chris's children?
Don't step on the cat's tail.
This isn't my book. It's my sister's. (= my sister's book)
✓ my friend's mother — but: the mother of the man we met yesterday
📌
Note:Remarque : We say a woman's hat (= a hat for a woman), a boy's name (= a name for a boy), a bird's egg (= an egg laid by a bird). The -'s can express purpose or relationship, not just literal possession. On dit a woman's hat (= un chapeau pour femme), a boy's name (= un prénom de garçon), a bird's egg (= un œuf pondu par un oiseau). Le -'s peut exprimer le but ou la relation, pas seulement la possession littérale.

B

Singular vs Plural Apostrophe

Apostrophe Singulier vs Pluriel

The position of the apostrophe depends on whether the noun is singular or plural.

La position de l'apostrophe dépend de si le nom est singulier ou pluriel.

Noun typeRuleExample
Type de nomRègleExemple
SingularSingulieradd -'smy sister's room (one sister)
ajouter -'smy sister's room (une sœur)
Plural ending in -sPluriel en -sadd apostrophe ' onlymy sisters' room (two or more)
ajouter seulement 'my sisters' room (deux ou plus)
Irregular plural (not -s)Pluriel irrégulieradd -'sthe men's room / a children's book
ajouter -'sthe men's room / a children's book
Two ownersDeux possesseursadd -'s to last nounJack and Karen's children
ajouter -'s au dernierJack and Karen's children
⚠️
Common errors:Erreurs courantes : the Carters's house → ✓ the Carters' house  ·  ✗ childrens' book → ✓ children's book (children is already plural — add -'s) the Carters's house → ✓ the Carters' house  ·  ✗ childrens' book → ✓ children's book (children est déjà pluriel — on ajoute -'s)

C

of… for Things and Ideas

of… pour les Choses et les Idées

For things, ideas, and inanimate objects, we normally use of rather than -'s. We also use of for: beginning/end/middle, top/bottom, front/back/side.

Pour les choses, les idées et les objets inanimés, on utilise normalement of plutôt que -'s. On utilise aussi of pour : début/fin/milieu, haut/bas, avant/arrière/côté.

✓ Use -'s (people/animals)

✓ Utiliser -'s (personnes/animaux)

Tom's computer
the cat's tail
my sister's name
the dog's owner

✓ Use of (things/ideas)

✓ Utiliser of (choses/idées)

the temperature of the water
the name of the book
the beginning of the month
the back of the car

D

Organisations and Places

Organisations et Lieux

For organisations (groups of people), you can usually use either -'s or of. For places, we use -'s.

Pour les organisations (groupes de personnes), on peut généralement utiliser l'un ou l'autre. Pour les lieux, on utilise -'s.

Organisations: the government's decision = the decision of the government
Organisations: the company's success = the success of the company
Places: the city's streets  ·  the world's population  ·  Italy's prime minister

E

-'s with Time Words

-'s avec les Mots de Temps

We use -'s with time words (yesterday, next week, today, tomorrow, Monday, etc.) and with periods of time (a week's holiday, three weeks' holiday).

On utilise -'s avec les mots de temps (yesterday, next week, today, tomorrow, Monday, etc.) et avec les périodes de temps (a week's holiday, three weeks' holiday).

Time words: yesterday's newspaper  ·  next week's meeting  ·  today's news
Periods: a week's holiday  ·  three weeks' holiday  ·  ten minutes' walk
💡
Note the apostrophe position with time periods: singular → a week's holiday (week's) / plural → three weeks' holiday (weeks' — apostrophe after the s). Notez la position de l'apostrophe avec les périodes : singulier → a week's holiday / pluriel → three weeks' holiday (apostrophe après le s).

-'s and of — Exercises-'s et of — Exercices

Check your answers instantly

Vérifiez vos réponses instantanément

EX 1

Rewrite using -'s or -' where more natural.

Réécrivez en utilisant -'s ou -' lorsque c'est plus naturel.

Type the more natural form (or "OK" if of… is correct).

Tapez la forme plus naturelle (ou "OK" si of… est correct).

1.
2.
3.
4.
5.
6.
7.
8.
Answers: 1. Chris's children  ·  2. your friend's umbrella  ·  3. OK (top of the page — thing)  ·  4. James's daughter  ·  5. our neighbours' garden  ·  6. David's hair  ·  7. the government's policy (or OK)  ·  8. my best friend's party
EX 2

Choose the correct form: singular -'s, plural -', or irregular -'s.

Choisissez la bonne forme : singulier -'s, pluriel -', ou -'s irrégulier.

Write only the possessive form of the word in brackets.

1.
2.
3.
4.
5.
6.
7.
8.
Answers: 1. cat's  ·  2. children's  ·  3. Switzerland's  ·  4. parents'  ·  5. Shakespeare's  ·  6. someone else's  ·  7. men's  ·  8. Tom's
EX 3

Rewrite the underlined time references using -'s or -s'.

Réécrivez les références temporelles en utilisant -'s ou -s'.

1.
2.
3.
4.
5.
6.
Answers: 1. Tomorrow's meeting  ·  2. Last week's storm  ·  3. The town's only cinema  ·  4. two hours' drive  ·  5. a 20 minutes' walk  ·  6. a week's holiday
EX 4

Correct the mistake or write OK.

Corrigez l'erreur ou écrivez OK.

1.
2.
3.
4.
5.
6.
Answers: 1. the temperature of the water  ·  2. OK  ·  3. the beginning of the month  ·  4. the children's toys  ·  5. OK  ·  6. the mother of the man we met yesterday

Frequently Asked Questions

Questions fréquentes

When do I use -' (apostrophe only, without s)?Quand utilise-t-on -' (apostrophe seule, sans s) ?

When the noun is already plural and ends in -s: my sisters' room, the Carters' house, three weeks' holiday. If the plural does NOT end in -s (men, women, children, people), use -'s: the men's room, a children's book.

Quand le nom est déjà pluriel et se termine en -s : my sisters' room, the Carters' house. Si le pluriel ne se termine pas en -s (men, women, children), on utilise -'s : the men's room, a children's book.

Can I say "the car's back"?Peut-on dire "the car's back" ?

Generally no — for things and inanimate objects we prefer of: the back of the car, the top of the hill, the beginning of the month. The -'s is reserved mainly for people, animals, organisations, places, and time expressions.

Généralement non — pour les choses et objets inanimés on préfère of : the back of the car, the top of the hill. Le -'s est réservé principalement aux personnes, animaux, organisations, lieux et expressions de temps.

What about "a friend of mine" — is that the same as -'s?Qu'en est-il de "a friend of mine" — est-ce la même chose que -'s ?

It has the same possessive meaning but a different structure: a friend of mine = one of my friends. You use mine/yours/his/hers/ours/theirs after of — never a friend of me. You can also say a friend of Tom's (= one of Tom's friends).

Le sens possessif est le même mais la structure est différente : a friend of mine = un de mes amis. On utilise mine/yours/his/hers/ours/theirs après of — jamais a friend of me. On peut aussi dire a friend of Tom's (= un des amis de Tom).

Can organisations use both -'s and of…?Les organisations peuvent-elles utiliser -'s et of… ?

Yes! Organisations are groups of people, so both forms work: the government's decision = the decision of the government. Both are correct. For places, -'s is preferred: the city's streets, Italy's economy.

Oui ! Les organisations sont des groupes de personnes, donc les deux formes fonctionnent : the government's decision = the decision of the government. Pour les lieux, on préfère -'s : the city's streets, Italy's economy.

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-'s and of — Quiz

-'s et of — Quiz

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