John 1:25

καὶ ἠρώτησαν αὐτὸν καὶ εἶπαν αὐτῷ· τί οὖν βαπτίζεις, εἰ σὺ οὐκ εἶ ὁ Χριστὸς οὐδὲ Ἡλείας οὐδὲ ὁ προφήτης;

καὶ conjunction "and"

ἠρώτησαν verb aorist active indicative 3rd plural from ἐρωτάω (I ask) "they asked"

αὐτὸν pronoun accusative masculine singular "him"

καὶ conjunction "and"

εἶπαν verb aorist active indicative 3rd plural from εἶπον (I say) "they said"

αὐτῷ pronoun dative masculine singular "to him"

τί interrogative pronoun "why"

οὖν conjunction "then"

βαπτίζεις verb present active indicative 2nd singular from βαπτίζω (I baptize) "you baptize"

εἰ conjunction "if"

σὺ pronoun 2nd singular "you"

οὐκ negative particle "not"

εἶ verb present active indicative 2nd singular from εἰμί (I am) "you are"

ὁ definite article nominative masculine singular "the"

Χριστὸς noun nominative masculine singular "Christ"

οὐδὲ conjunction "neither"

Ἡλείας proper noun nominative masculine singular "Elijah"

οὐδὲ correlative conjunction "nor"

ὁ definite article nominative masculine singular "the"

προφήτης noun nominative masculine singular "prophet"

Rough Word-by-word:
And they asked him and said to him, "Why then you baptize if you not you are the Christ neither Elijah nor the prophet?"

Smooth Translation:
And they asked him and said to him, "Why then are you baptizing if you are not the Christ, neither Elijah nor the prophet?"