Grammar Point verbs ending with ‘ed’: The past simple
Example
He walked to school.
He did not walk to school.
Did he walk to school?
Explanation
Verbs ending with ed indicated an action in the past. Compare
I talk with the office. (present)
I talked with the office. (Past)
Structure
Subject + verb stem (simple for of the verb)
Did + subject + verb
Subject + did not (didn’t) + verb

Remember
In English there are many irregular verbs so this rule applies only with some verbs.
In English there are exceptions. We will go over the exceptions later on.