Verbi ausiliari e principali
To be/ to have
do-does = simple present
did = simple past
In these sentences do and did are auxiliary verbs, instead the others "do" are the main verbs.
Can- could (potere)
May- might (potere)
Must- should (dovere)
Will (futuro)
Would (condizionale)
Shall (I- we)
* Regular verbs
To work
worked
worked
* Irregular verbs
to go
went
gone
to eat
ate
eaten