The Genitive Case

Inglês

The genitive case, most known as the ' or 's at the end of nouns, is used to show a relation between the subject and the object. It can be of possessive nature or sometimes descriptive nature. It's easy, but there are some rules to use it correctly:

It is more common to use it with animated beings: the boy's house, the dog's tail, the Queen's crown, the doctor's appointment...

It's not OK to use it with objects: you're not going to say my house's roof, but the roof of my house; or the car door/the door of the car instead of the car's door

Although it's not common to use it with things or abstract nouns, we can use it to talk about time, measurements, countries, planets and groups of people (government, company, team...): in a year's time, the government's decision, the company's employees, Saturn's rings, Brazil's debt...

When using it with singular nouns, you just have to add 's, even if your noun/name ends in "s" - you can also choose, for these cases, to use only ': Lucas's car or Lucas' car, mom's gift, the Ramos's house or the Ramos' house...

When using it with plural nouns, you should just add the ': the girls' cell phones, some governments' opinions...

When talking about irregular plural nouns, you should add the 's normally: people's jobs, men's opinions...

If you're talking about one thing belonging or concerning more than one person/group, only the latter should have the 's added: Charles and Miranda's wedding; Sally and Susan's car;

If you're talking about more than one person/group and different objects/people concerning them, add the 's to both: John's and Jack's parents (they are not sibblings, so they have different mothers and fathers), men's and women's clothes (both wear clothes, but usually men's and women's clothes are different).