perfect present vs simple past

Simple Past	Present Perfect Simple
irregular verbs: see 2nd column of irregular verbs Example: I spoke	irregular verbs: form of 'have' + 3rd column of irregular verbs Example: I / you / we / they have spoken he / she / it has spoken
regular verbs: infinitive + ed Example: I worked	regular verbs: form of 'have' + infinitive + ed Example: I / you / we / they have worked he / she / it has worked
Exceptions
Exceptions when adding 'ed': when the final letter is e, only add d Example: love - loved after a short, stressed vowel, the final consonant is doubled Example: admit - admitted final l is always doubled in British English (not in American English) Example: travel - travelled after a consonant, final y becomes i (but: not after a vowel) Example: worry - worried but: play - played