How you know a verb is regular or irregular?

Answer 1

A regular verb will simply add -ed on to the end to form the past tense and past participle.

For example, to form the past tense of the verb 'laugh', we add -ed to create 'laughed' which is also the past participle of the verb.

Irregular verbs, however, don't add -ed to form the past tense or past participle.

For example, the past tense of the verb 'see' becomes 'saw' whilst the past participle becomes 'seen'.

Answer 2

Regular verbs form their past tense by adding "-ed" to the base form (e.g. walk -> walked), while irregular verbs change their spelling to form the past tense (e.g. go -> went). It is important to memorize the irregular past tense forms as they do not follow a consistent pattern.