2. The distinction between regular verbs and irregular verbs is a very simple one:
Regular Verbs
Those verbs that form their past participle with ‘d’ or ‘ed’ are regular verbs. These
verbs do not undergo substantial changes while changing forms between
tenses.
If the verb ends with a vowel, only ‘d’ is added. For example:
PRESENT TENSE PAST TENSE
Share Shared
Scare Scared
Dare Dared
If the verb ends with a consonant, ‘ed’ is added. For example:
PRESENT TENSE PAST TENSE
Want Wanted
Shout Shouted
Kill

3. Irregular Verbs
Those verbs that undergo substantial changes when changing forms between
tenses are irregular verbs. The changed forms of these verbs are often
unrecognisably different from the originals.
For example:
PRESENT TENSE PAST TENSE
Go Went
Run Ran
Think Thought