The simple past is used to describe an action that
occurred and was completed in the past. The simple past
is formed by adding -ed to the base form of the verb (the
infinitive without to).base form + ed = simple past
walk walked ,push pushed greet ,greeted watch watched
.
Simple past of irregular verbs.
But there are verbs that to do the simple past and past participle
not receive ED at the end, but other endings that do not follow a
single rule and there is a huge list of these verbs, which are written
in different ways. These are called irregular verbs.
Did and Didn't
Did it help the corresponding questions in the past, it should not be translated as mean question.
(Just as DO) Have DID NOT is DID NOT contraction that is the negative of the sentence also in the
past, the verb remains in the present.