Use the past simple to talk about activities or routines which take place at a specified time in the past. Notice that all subjects take the same conjugation of the verb. Regular verbs end in '-ed'.
visit - visited
enjoy - enjoyed
Irregular verbs have various forms and each verb needs to be learned.
see - saw
think - thought
The past simple is used to express a finished past action which occurs at a specific moment in the past.
She visited Iran last month.
They didn't go to Tom's party last weekend.
Where did you go on vacation last summer?
The following time signifiers often indicate a specific point in time.
in ... (plus a year or month)
when ... (plus a phrase)
They had lunch at home last week.
He left the company many years ago.
Susan bought a new car in May.
He telephoned his friend in Rome yesterday.
I played golf when I was a teenager.
Subject + past form of verb + object(s) + time
They flew to Chicago last month.
Peter completed his course three weeks ago.
Subject + did + not + base form of verb + object(s) + (time)
They didn't expect to see you at Christmas.
She didn't understand the question.
(Wh?) + did + subject + base form of verb + (object(s))+ (time)?
Where did you study French?
When did you arrive last week?