Deci trecutul simplu il folosesti cand e vorba de o actiune trecuta, de exemplu:
I finished my homework 2 hours ago.
Prezentul perfect atunci cand e vorba de o realizare, fara data fixa, deci fara: yesteday, ago, etc.
I have finished my homework.
Tot timpul cand e cu ago, yesterday, last year e trecutul simplu, iar cand e vorba doar de o realizare e prezentul perfect.
I had a shower last year.
I have had a shower.
Am uitat, prezentul perfect se mai formeaza si cu: since, for, just, already sau yet.
De exemplu:
I have just finished my homework.
I have finished my homeowrk already.
I have not fnished my homework yet.