Breakdown of Compra uma dúzia de bolos para a festa.
de
of / from / by (means of transport) / wearing (attire)
um
a / an / some (all forms)
comprar
to buy
o bolo
the cake
Questions & Answers about Compra uma dúzia de bolos para a festa.
Why is the verb compra instead of compras if this is an informal command to a friend?
To give a command to someone you address as tu (informal you), Portuguese uses the affirmative imperative. For regular verbs ending in -ar like comprar, you just drop the s from the present tense compras, giving us compra. If you were speaking formally to someone as você, you would say compre.
Why is there a de before bolos? In English we just say a dozen cakes.
In Portuguese, when you use a noun that expresses a quantity or measurement, you must connect it to the item with the preposition de (of). So uma dúzia de bolos literally translates to a dozen of cakes. You will also see this rule with weights, like um quilo de maçãs (a kilo of apples).
Why do we use para instead of por to say for the party?
The preposition para is used here because it shows the destination or purpose of the cakes. They are meant for the party. You generally use para when talking about intended recipients, final destinations, or deadlines, whereas por is often used for the cause, route, or duration of something.
How would I ask for half a dozen cakes instead?