John 1:21

καὶ ἠρώτησαν αὐτόν· τί οὖν; Ἡλείας εἶ; λέγει· οὐκ εἰμί. ὁ προφήτης εἶ σύ; καὶ ἀπεκρίθη· οὔ.

καὶ conjunction "and"

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

αὐτόν pronoun accusative masculine singular "him"

τί prounoun nominative neuter singular "what"

οὖν conjunction "then"

Ἡλείας proper noun "Elijah"

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

λέγει verb present active indicative 3rd singular from λέγω (I say) "he said"

οὐκ negative particle "not"

εἰμί verb present indicative 1st singular from εἰμί (I am) "I am"

ὁ definite article nominative masculine singular "the"

προφήτης noun nominative masculine singular "prophet"

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

σύ pronoun 2nd singular nominative "you"

καὶ conjunction "and"

ἀπεκρίθη verb aorist middle deponent 3rd singular from αποκρίνομαι (I answer) "he answered" (note: passive in form, but active in meaning so it is aorist middle deponent, not aorist passive.)

οὔ negative particle "no"

Rough Word-by-word:
And they asked him what then Elijah are you? he says not I am. the prophet are you? and he answered no.

Smooth Translation:
And they asked him, "What then, are you Elijah?" He said "I am not." "Are you the prophet?" And he answered, "No."