Present Perfect

This tense is called [present] perfect because we can see (now, in the present) the result of what has been perfected, done, carried out, achieved.
I am drunk because I have drunk too much.
μεθύω, ἄγαν γὰρ πέπωκα.

Compare the personal endings
Present      Perfect
drinks  Who  has drunk
 πίν ω   I   πέπωκ α 
 πίν εις   you (sg)   πέπωκ ας 
 πίν ει   he/she/it   πέπωκ ε (ν)
 πίν ομεν   we   πεπώκ αμεν 
 πίν ετε     you (pl)   πεπώκ ατε 
 πίν ουσιν   they   πεπώκ ασιν