simple past

build it

regular verbs

irregular verbs

simple past = infinitive + ED

I talked
you waited
she asked
we answered

special: drop the end -E of the infinitive

invite -> you invited
receive -> they received

Irregular means that these verbs don't follow rules.
And so we can't help with a general rule.
There is only one way to know the correct form: memorize it.

Some examples:
to write -> I wrote
to come -> you came
to leave -> she left
to begin -> they began

Here is a list of irregular verbs and their forms.
If you click the link, you can see the list.
If you right click it, you can download the list to your computer.