Participles are special infinite infinite = unchangeable
forms of the verb. There are two different participles for each verb:
the present participle
the past participle
The present participle is only used to create structures with present or active meaning.
The past participle is used to create structures with past or passive meaning.
The past participle is formed by adding the ending '-ed' to the verb.
A silent -e at the end of the verb is dropped (e.g. care - cared, argue - argued).
'y' after consonant at the end of the verb
becomes 'i' (e.g. cry - cried, fry - fried). (But:
Single consonants after a short vowel are doubled
(e.g. sin - sinned, outwit - outwitted).
Irregular verb forms must be learned by heart. (Sorry. I know how this feels.) Lists of irregular
verbs usually come as a table with three columns, of which
the first column is the infinitive, ...
the second column is the simple past form and ...
the third column is the past participle.
Every English dictionary contains such a list.
Additionally, the alphabetic section gives you the past and past participle forms of each irregular verb.
So if you don't see such an entry, the verb must be regular.