Ter (to have) — present tense
ter is one of the most-used verbs in Portuguese — and it's irregular. You met tenho, tens, and tem in lesson 5; now you'll lock in the rest. Ter means 'to have' (possession), but it also drives a stack of idioms that English builds with 'to be': ter fome ('to be hungry', literally 'to have hunger'), ter … anos ('to be … years old', literally 'to have … years').
The full conjugation
eu tenho = I have. tu tens = you have. ele tem / ela tem / você tem = he/she has, you have. nós temos = we have. eles têm / elas têm / vocês têm = they have, you all have. The chant: tenho, tens, tem, temos, têm. The plural têm is written with a circumflex — that's how the spelling distinguishes it from the singular tem, even though in everyday speech they sound nearly identical.
Possession
Same job as English 'have': Tenho um gato = I have a cat. Tens um livro? = Do you have a book? A Ana tem dois irmãos = Ana has two brothers. Nós temos uma casa em Lisboa = We have a house in Lisbon. As always, the subject pronoun is optional — the verb form already tells you who.
The 'ter' idioms — where English uses 'to be'
ter fome = to be hungry (literally 'to have hunger'). ter sede = to be thirsty. ter sono = to be sleepy. ter frio = to be cold (the person, not the weather). ter calor = to be hot. ter medo = to be afraid. ter razão = to be right. Tenho fome = I'm hungry. Eles têm sede = They're thirsty. Don't reach for estar here — Portuguese hard-wires these states to ter.
Age — 'ter … anos'
Portuguese asks age with ter, not ser. Quantos anos tens? = How old are you? (literally 'how many years do you have?'). The answer: Tenho vinte anos = I'm twenty. Always include anos — saying just Tenho vinte sounds incomplete, like English 'I have twenty'.
PT vs BR: 'há' vs 'tem' for 'there is/are'
Standard 'there is/are' in Portugal is há (from the verb haver): Há um gato na casa = There's a cat in the house. Há cinco livros na mesa = There are five books on the table. In everyday Brazilian speech, people use tem instead: Tem um gato na casa, Tem cinco livros na mesa — exactly the same meaning, just the ter verb pressed into service. Both are correct in their register; há is the safer bet in writing.
