Past Simple and Past Continuous

PAST SIMPLE- Form: Verb + ed (Regular vebs) / List of irregular verbs

We use it: To talk about a finished action in the past.

Affirmative: Last Saturday Sam visited his parents at the campsite.
Negative: Last Saturday Sam didn´t visit his parents at the campsite.
Interrogative: Did Sam visit his parents at campsite last Saturday?

Time expressions: Yesterday, two (days/weeks/years) ago, last (week, month), in April, on 4th March, when.

PAST CONTINUOUS- Form: was/were + verb -ing

We use it: For actions which were in progress at a specific time in the past.

Affirmative: When I arrived at the beach, my friends were playing beach volley.
Negative: When I arrived at the beach, my friends weren´t playing beach volley.
Interrogative: Were they playing beach volley when you arrived at the beach?

Time expressions: While, yesterday, at (nine o´ clock/half past nine), all (morning/day).