Grammar Reference

Verbs

Past of regular verbs

To form the past simple of regular verbs, add -ed to the infinitive.
When the infinitive ends in e add -d.
When the infinitive ends in y, the y changes to i and then add -ed.

Infinitive Past simple
finish finished
decide decided
study studied

To form the negative past simple use didn't + infinitive.

To form a past simple question use did + infinitive.