Perfeito vs Imperfeito

The big past-tense decision: completed action or ongoing scene?

Use pretérito perfeito for…	Use pretérito imperfeito for…
A specific event that happened and ended	An ongoing or repeated past action
Ontem eu fui ao cinema. (I went)	Eu ia ao cinema todo sábado. (I used to go)
Comi um pastel. (I ate, once)	Eu sempre comia pastel na feira. (I always used to eat)
Background-to-event narration → the event	Background-to-event narration → the background

A classic combo: imperfect for the scene, perfect for the action that interrupted it.

Eu estava em casa quando o telefone tocou. "I was at home when the phone rang."

Pick the right tense

Cloze: pick the right past

Translate the mix