Possessives

Portuguese regular possessive adjectives and pronouns are somewhat similar to English, but there are some differences. In Portuguese, they follow a few rules.

English-like rules:

Their stem/base form gives information about the possessor (the person/thing who owns it).
Adjective possessives usually show up before the noun (while placing them afterwards is not strictly wrong, it’s very rare – usually a style choice in books and poems).

Differences:

The base form needs to be declined according to the gender and number of the noun it’s qualifying. (Just like adjectives and articles)
Possessive adjectives and pronouns in Portuguese are exactly the same. There is no extra "s" like in "your x yours"; the –s endings you may encounter are plural markers.
The regular possessive adjectives can be preceded by the corresponding definite article ("o meu", "a minha"...), but in Brazilian Portuguese using the article is mostly optional.

These are the regular pronouns and their inflections:

Owner	Masc. sing.	Fem. sing.	Masc. plural	Fem. plural
Eu	(o) meu	(a) minha	(os) meus	(as) minhas
Tu	(o) teu	(a) tua	(os) teus	(as) tuas
Você/Ele/Ela	(o) seu	(a) sua	(os) seus	(as) suas
Nós	(o) nosso	(a) nossa	(os) nossos	(as) nossas
Vós	(o) vosso	(a) vossa	(os) vossos	(as) vossas
Vocês/Eles/Elas	(o) seu	(a) sua	(os) seus	(as) suas

.
Examples:

O meu carro é vermelho = My car is red
Minha casa é azul = My house is blue
Meus gatos são brancos = My cats are white
As minhas meias são pretas = My socks are black

Alternative pronouns:

As you may have noticed, without context it’s impossible to discern which third person pronoun (você/ele/ela/vocês/eles/elas) the regular possessive is referring to. (Normally in these cases Duolingo accepts all possible translations if they make sense):

Seu cão = Your / His / Her / Their dog

In Brazil, using "seu" in simple sentences most of the times means "your(s)", but in sentences with some context, it tends to refer to the previously stated subject:

Eu não vi o seu casaco = I didn't see your coat
A menina vestiu seu casaco e saiu = The girl put on her coat and left

To avoid that confusion, there are other possessive pronouns whose declinations refer to the owner instead and do not decline according to the owned noun:

Owner	Poss. pronoun	Owner	Poss. pronoun
Ele	Dele	Eles	Deles
Ela	Dela	Elas	Delas
-	-	Vocês	De vocês

* - The form "de você" (singular) is not seen as a possessive form!
** - A popular informal one referring to "nós" is "da gente". It's not used in disambiguation, because "nosso(as)" is not ambiguous, but it's common in popular language due to "a gente" meaning "nós".

These are nothing but the personal pronoun preceded by a "de" preposition, creating an effect similar to "of him", "of her", "of them", "of yours". But unlike English, they are very natural in Portuguese.

Examples:

O coelho dela come cenoura = Her rabbit eats carrots
As moedas dele estão brilhando = His coins are shining
A casa deles é grande = Their house is big
Gosto do cachorro de vocês = I like your dog (you plural)
Isto vai mudar a vida da gente = This will change our life

Articles with possessive pronouns

While the possessive adjectives (coming before nouns) can have optional articles, the possessive pronouns (that don't precede nouns) must use the articles consistently.

One way of checking whether the article should be used is inverting the English sentence to the unusual "of him" form.
Then the article should behave in a similar way in both languages. (Please consider that this unusual English form is not commonly accepted as English translations in the system)

O cachorro dele quer água = His dog wants water (checking: the dog of him wants water - necessary article)

Sometimes, the article is optional, but meaning is changed:

Esses carros são meus = These cars are mine (checking: these cars are cars of mine)

Result: These cars belong to me
Esses carros são os meus = These cars are mine (checking: these cars are the cars of mine)

Result: These cars are the ones that belong to me

Using the article in these cases talks about "extra specific" things, suggesting there are probably other possibilities.

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