- How old are you? - Qual é a tua idade?

Informação retirada do livro Super Jet Line 2 - 6.º Ano, Texto Editores

How old	are	you?
	is	he? she?
	are	they?

I	am	ten years old.
He She	is
They	are

Note
I'm = I am
He's = he is
She's = she is
They're = they are