Possessive Forms of Nouns — English Grammar Exercises
boss's or bosses'? Tom and Sarah's or Tom's and Sarah's? — own it
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The possessive 's
| Noun type | Add | Example |
|---|---|---|
| singular noun | 's | the dog → the dog's tail |
| singular ending in -s | 's | the boss → the boss's office |
| plural ending in -s | ' only | the students → the students' books |
| irregular plural | 's | the children → the children's toys |
Watch out: the apostrophe goes before the -s for one owner and after it for several — the girl's room (one) vs the girls' room (several).
's or "of"?
- people, animals, organizations → usually 's: Anna's car, the company's decision
- things, places, abstract ideas → usually of: the roof of the house, the end of the street
Joint vs separate possession
- shared: Tom and Anna's house — one house (only the last name takes 's)
- separate: Tom's and Anna's cars — each person has their own
Time, distance and value
The possessive 's is also used with time, distance, and amounts:
a day's work, two weeks' holiday, ten minutes' walk, today's news, five pounds' worth
The double genitive
Use of + a possessive form to mean "one of several": a friend of mine, a colleague of my brother's.
Common mistakes
| ❌ | ✅ |
|---|---|
| the childrens' room | the children's room |
| the students's books | the students' books |
| a two weeks holiday | a two weeks' holiday |
| the friend of me | a friend of mine |
| a bus's station | a bus station |
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This is ___ umbrella — she left it here yesterday.
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Maria's
A singular name takes 's — Maria's.
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The ___ tail is long and very fluffy. (one dog)
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dog's
A singular noun takes 's — the dog's tail.
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The ___ books are all on the table. (several students)
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students'
A plural noun ending in -s takes only an apostrophe — the students' books.
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The ___ playground is behind the school. (the children)
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children's
'Children' is an irregular plural, so it takes 's — the children's playground.
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This is the ___ changing room. (the women)
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women's
'Women' is an irregular plural, so it takes 's — the women's changing room.
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My ___ house has a large garden. (my parents)
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parents'
A plural noun ending in -s takes only an apostrophe — my parents' house.
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Have you seen ___ new office? (the boss)
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the boss's
A singular noun ending in -s still takes 's — the boss's office.
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I really love my ___ cooking. (my grandmother)
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grandmother's
A singular noun takes 's — my grandmother's cooking.
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The ___ toys are all over the floor. (the babies)
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babies'
The plural of 'baby' is 'babies'; the plural possessive takes only an apostrophe — the babies' toys.
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We're going to ___ party tonight. (James)
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James's
A name ending in -s usually takes 's in modern English — James's party.
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My ___ bedroom is the biggest in the house. (my sister)
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sister's
A singular noun takes 's — my sister's bedroom.
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The ___ uniforms are bright blue. (the players)
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players'
A plural noun ending in -s takes only an apostrophe — the players' uniforms.
Possessive Forms of Nouns: Complete Grammar Reference
Possessive errors in English are among the most documented and persistent errors in learner corpora. Research from the Cambridge Learner Corpus shows that apostrophe errors affect approximately 20% of B1–B2 written samples, and the errors are not random — they cluster around a small set of rule conflicts that this topic addresses directly. The challenge is that English uses three overlapping systems (apostrophe 's, bare s', of-phrase) whose selection depends on animacy, number, context, and sometimes idiom. Add joint vs separate possession, time expressions, implied place nouns, and the double genitive, and the possessive system becomes one of the most rule-dense areas of English grammar at intermediate level. These 45 questions across 3 practice blocks address all six areas systematically.
Apostrophe Basics: 's vs s'
The apostrophe position depends entirely on the base form of the noun — not on pronunciation or on how many letters the word has. The rule is two-step: first, form the plural; second, check whether that plural ends in -s. If it does, add only an apostrophe after the -s. If it does not, add 's.
- Singular nouns → always add 's, even if the noun ends in -s: boss → boss's, James → James's
- Regular plurals ending in -s → add only ': students → students', parents → parents'
- Irregular plurals not ending in -s → add 's: children → children's, women → women's, people → people's
the children's toys (irregular plural — no -s) | the women's team (irregular plural — no -s)
my boss's office (singular ending in -s — still add 's)
's vs Of-Phrase: The Animacy Divide
English does not apply the possessive 's indiscriminately to all nouns. The choice between 's and an of-phrase broadly follows the animacy hierarchy: the higher the owner ranks on the scale (people > institutions/organisations > animals > inanimate objects), the more natural 's becomes. For inanimate objects — particularly their physical parts — the of-phrase or a compound noun is preferred.
- People and animals: the director's office, the dog's lead
- Organisations and institutions: the company's strategy, the government's decision
- Geographical entities with 's in idiom: the world's economy, the city's population
- Physical parts of inanimate objects → of-phrase or compound: the roof of the house, the beginning of the film, table leg (not table's leg), car door handle (not car's door handle)
the banks of the river (physical part of object) | the world's economy (set idiom with 's)
Joint vs Separate Possession
When two or more people share a single item, English marks only the final name with 's. When each person owns their own separate item, every name receives 's. The distinction is meaningful and cannot be inferred from context alone — it must be encoded explicitly in the apostrophe placement.
Mark's and Lisa's offices — each has a different office (separate possession)
David and Anna's house is near the beach — one house, shared (joint)
Jake's and Mia's cars are different models — separate cars (separate)
Time, Distance, and Value Expressions
English uses a possessive structure with time periods, distances, and monetary values to express the relationship between a quantity and what it measures or produces. The apostrophe position follows the standard rule — singular time words add 's, plural time words add only an apostrophe — but many learners omit the apostrophe entirely in these expressions, treating them as compound nouns.
a week's holiday (singular) | two weeks' notice (plural)
a good night's sleep | ten minutes' walk | six months' salary
Analysis of the British National Corpus shows that time possessive expressions are among the twenty most frequent possessive patterns in everyday written English, making them a high-priority accuracy target for B1–B2 learners.
Places and Businesses: The Dropped Noun
English regularly omits the noun after possessive 's when the type of place is understood from context. This pattern is established for healthcare providers, service businesses, and people's homes. Corpus data confirms it is near-universal in spoken British English and appears frequently in informal written English.
She left her bag at the hairdresser's. (= the hairdresser's salon)
We had dinner at my parents'. (= my parents' house)
I'll pick it up from the pharmacist's. (= the pharmacist's shop)
The apostrophe is obligatory in these expressions — omitting it (writing at the hairdresser) implies the person rather than the place.
The Double Genitive
The double genitive combines the of-phrase with a possessive 's: a/an + noun + of + possessive noun. It is used when the indefinite article introduces one item from a larger set belonging to someone. Without the 's, the preposition of signals a different relationship — about or depicting rather than belonging to — and the sentence means something different.
a friend of Sarah = a friend who depicts Sarah — different meaning
an idea of Tom's = one of Tom's ideas
a painting of Picasso's = a painting Picasso created (not a portrait of him)
The pattern extends naturally to pronouns: a friend of mine, a colleague of yours, a neighbour of theirs. Learner corpora show that the double genitive is mastered reliably only at B2 level, with the missing 's ('a friend of Sarah') being the most common error form.
Common Mistakes
✗ My parents's house is near the lake. → ✓ My parents' house is near the lake. (regular plural — apostrophe after s only)
✗ The childrens' toys were on the floor. → ✓ The children's toys were on the floor. (irregular plural — no extra -s)
✗ I need to replace the table's leg. → ✓ I need to replace the table leg. (inanimate object part — use compound noun)
✗ We had dinner at Tom's and Sarah's apartment. → ✓ We had dinner at Tom and Sarah's apartment. (joint possession — one 's at the end)
✗ Sam and Dan's laptops are different models. → ✓ Sam's and Dan's laptops are different models. (separate possession — 's on both)
✗ I only had one hours sleep. → ✓ I only had one hour's sleep. (singular time expression — add 's)
✗ We're going on three weeks holiday. → ✓ We're going on three weeks' holiday. (plural time — apostrophe after s)
✗ She left her bag at the hairdresser. → ✓ She left her bag at the hairdresser's. (place noun dropped — possessive required)
✗ A friend of Sarah told me about the party. → ✓ A friend of Sarah's told me about the party. (double genitive — 's required)
Frequently Asked Questions
When do you add 's and when do you add just an apostrophe (s')?
The rule depends on whether the noun is singular or plural and how the plural is formed. Singular nouns — including those ending in -s — add 's: the boss's office, James's car. Regular plural nouns already ending in -s add only an apostrophe after the -s: the students' essays, my parents' house. Irregular plural nouns that do not end in -s add 's: children's playground, women's changing room, people's opinions. The key question is: what is the base plural form? If it ends in -s, add only an apostrophe. If it doesn't, add 's.
When do you use 's and when do you use an of-phrase?
's is the natural choice for people, animals, organisations, institutions, and time/distance/value expressions: the director's office, the government's decision, a week's holiday. The of-phrase is more natural with inanimate objects and physical parts of things: the roof of the house, the beginning of the film, the colour of the sky. For parts of objects, English also frequently uses compound nouns with no apostrophe: table leg (not table's leg), car door handle (not car's door handle). The rule of thumb: if you can replace it with a person's name, use 's. If the owner is an inanimate object, prefer of or a compound noun.
What is joint possession and how do you show it with apostrophes?
Joint possession means two or more people share a single item. In that case, only the last name takes 's: Tom and Sarah's wedding (one shared wedding). Separate possession means each person has their own. In that case, every name takes 's: Mark's and Lisa's offices (different offices). The grammar follows the logic: if one apostrophe covers both people, it must go on the final name in the pair. If each person owns their own item independently, each name needs its own possessive marker.
What is the double genitive and why is 'a friend of Sarah's' correct?
The double genitive (also called the 'of-possessive') is the construction: a/an + noun + of + possessive. 'A friend of Sarah's' means one of Sarah's friends — the possessive 's is required because the sentence implies Sarah has multiple friends and you are referring to one of them. Without the 's, the meaning changes: 'a friend of Sarah' would suggest the friend is somehow about Sarah or depicts her. The pattern extends to pronouns (a friend of mine, a colleague of yours) and to plural names (a neighbour of the Smiths'). The double genitive is obligatory when the indefinite article a/an precedes the noun.
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