past simple

use:

• states, events, and actions that started and finished at a specific time in the past - example: i visited paris last summer.
• a past action interrupting another action or a situation - example: while we were having supper, the phone rang.
• action in the past that finished - example: we had supper and then we cleared the table.

signal words: yesterday, last night, last week, three months ago, on monday / tuesday ..., in the past, before, ago, etc.

vs

past continuous

use:

• actions in progress at a particular time in the past - example: at 8 pm last night, i was watching a movie.
• an action in progress in the past interrupted by another action - example: i was studying, and my brother was playing chess when the phone suddenly rang.
• to set the scene at the beginning of a story and to give background information - example: the rain poured outside as i sat in the cozy café, savoring the aroma of freshly brewed coffee and the soothing notes of a distant piano.

signal words: at that time, while, when, as, as long as, during, etc.

used to

use:

• habits and situations that only happened in the past - example: i used to play the piano when i was a child.
• actions that happened regularly in the past - example: she used to go jogging every morning.
• past habits and situations in contrast with the present - example: i used to live in the countryside; now, i live in the city.

form:

• affirmative: subject + used to + base form
• negative: subject + didn't (did not) + use to + base form
• interrogative: did + subject + use to + base form?
• short answers: yes, + subject + did. / no, + subject + didn't.