|An action happened once in the past.|
|yesterday, ago, in 1993, last Monday, last month, last year|
2nd verb form
|Yesterday I played hide-and-seek with my cats.
I built a huge sand fortress last holidays.
I met my husband in 2001.
didn't + 1st verb form
|They didn't have a swim lesson last Monday.
I didn't expect such a party last sunday!
I didn't see you in the school last week.
did + 1st verb form
|Where did I see you last Monday?
Did you eat my piece of the cake yesterday?
What did I give to you yesterday?