Present Perfect Tense: Already and Yet

Already and yet are used with the present perfect tense to express the idea that something has (or has not) happened before the present moment.
Already is placed in the middle of the sentence between the auxiliary have and the past participle. Yet is placed at the end of a sentence.
Examples: I have already done my homework. (ya)
I haven’t done my homework yet. (todavía no)

Click here to see a list of verbs with irregular past participle forms.