A frequent question that comes to me is about the verbs ser and estar. Many students do not realize the use and the difference between the verb ser and estar because the most often translated as the verb be in English... there is one word in English for two in Portuguese, no wonder English speaking learners get confused!
But first, Just as a quick reminder about verb ser and estar conjugated in the Present Indicative tense as follows:
O meu nome é Ana. My name is (permanently/always) Ana.
O sol é amarelo. The sun is (permanently/always) yellow.
Eu sou alta. I am (permanently/always) tall.
Eu sou bióloga. I am Biologist.
Eu sou vegetariana. I am vegetarian.
The verb ser also expresses the hour, day, date, time.
São oito e vinte minutos. It's eight twenty.
É meia-noite. It's midnight
Hoje é dia 7 de janeiro. Today is January 7
Hoje é sábado. Todays is Saturday.
A livraria é ao lado da loja das fotocópias. The bookstore is next to the shop of the photocopies.
A casa-de-banho é ao fundo do corredor. The en-suite is down the hall.
Eu hoje estou inteligente. Today I look intelligent (at this time).
A cerveja está gelada. The beer is (temporarily) cold.
Eles estão cansados. They are (temporarily) tired.
Eles estão contentes. They're happy.
O carro está perto do cinema. The car is near the cinema.
O Pedro está em casa da avó. Pedro is in grandma's house.
O gato está debaixo da mesa. The cat is under the table.
Hoje estão 5 graus. Today is five degrees.
Eu sou Portuguesa. I am (permanently/always) Portuguesa.
Ele é casado. He is (somewhat permanently) married.
A Susana está no ginásio. Susan is (temporarily) at the gym.
Os bolos desta pastelaria geralmente são óptimos, mas hoje não estão muito bons. The cakes of this pastry are usually great, but today are not very good.
Ela é bonita, ela está bonita.
She is not (permanently/always) beautiful, she is (temporarily) beautiful.
In the first case, we mean that the girl is naturally pretty (lucky girl). In the second case, mean that she is prettier than usual (maybe she dress nice clothes, got a new haircut, or otherwise accessorized herself, or makeup). We use the second case when we want to call attention to the fact that she is prettier due to some temporary condition.
Ele está doente. He is (temporarily disease) sick
Ele é doente. He is (permanently, like a cronic) sick.
Another example, in both cases translate to 'he is sick'. However, the first sentences says that he isn't usually sick, but is at the moment. The second case means that he is sick now, was in the past and will be in the future, for example a hereditary disease, or chronic diseases.
Eles são gordos. They are (permanently, if they born and still) fat.
Eles estão gordos. They are (temporarily, if they usually are thin) fat.
For the past and future, use the same rules:
Eu estive doente. I was sick.
Os bolos não eram bons. The cakes were not good.
The difference between the two is sometimes jokingly used by Portuguese and Brazilians:
Ela não está bonita, ela é bonita.
She is not (temporarily) beautiful, she is (permanently/always) beautiful.