John 2:18

ἀπεκρίθησαν οὖν οἱ Ἰουδαῖοι καὶ εἶπαν αὐτῷ· τί σημεῖον δεικνύεις ἡμῖν, ὅτι ταῦτα ποιεῖς;

Rough Word-by-word:
They answered therefore the Jews and they said to him, "What sign you show to us, that these things you do?"

Smooth Translation:
Therefore the Jews answered and said to him, "What sign do you show us, that you do these things?"

ἀπεκρίθησαν verb aorist passive indicative 3rd plural from ἀποκρίνομαι (I answer) "They answered" (note the sign of the aorist passive, θη)

οὖν adverb "therefore"

οἱ definite article nominative masculine plural "the"

Ἰουδαῖοι adjective nominative masculine plural "Jews"

καὶ conjunction "and"

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

αὐτῷ pronoun dative masculine singular "to him"

τί relative pronoun "what"

σημεῖον noun accusative neuter singular "sign"

δεικνύεις verb present active indicative 2nd singular from δεικνύω (I show) "you show"

ἡμῖν pronoun dative 1st plural "to us"

ὅτι conjunction "that/because"

ταῦτα demonstrative pronoun accusative neuter plural "these things"

ποιεῖς verb present active indicative 2nd singular from ποιέω (I do/I make) "you do"