John 6:31

οἱ πατέρες ἡμῶν τὸ μάννα ἔφαγον ἐν τῇ ἐρήμῳ, καθώς ἐστιν γεγραμμένον· ἄρτον ἐκ τοῦ οὐρανοῦ ἔδωκεν αὐτοῖς φαγεῖν.

Rough Word-by-word:
the fathers of us the manna they ate in the desert, even as is having been written, "Bread from the heaven he gave to them to eat."

Smooth Translation:
Our fathers ate the manna in the desert, even as it written, "Bread from heaven he gave them to eat."

οἱ definite article nominative plural masculine "the"

πατέρες noun nominative plural masculine "fathers"

ἡμῶν pronoun genitive 1st plural "of us"

τὸ definite article nominative singular neuter "the"

μάννα noun nominative singular neuter "manna"

ἔφαγον verb aorist active indicative 3rd plural from ἐσθίω (I eat) "they ate"

ἐν dative preposition "in"

τῇ definite article dative singular feminine "the"

ἐρήμῳ noun dative singular feminine "desert"

καθώς conjunction "even as"

ἐστιν verb present indicative 3rd singular from εἰμί (I am) "it is"

γεγραμμένον perfect passive participle accusative singular neuter from γράφω (I write) "having been written"

ἄρτον noun accusative singular masculine "bread"

ἐκ genitive preposition "from, out of"

τοῦ definite article genitive singular masculine "the"

οὐρανοῦ noun genitive singular masculine "heaven"

ἔδωκεν verb aorist active indicative 3rd singular from δίδωμι (I give) "he gave"

αὐτοῖς pronoun dative plural masculine "to them"

φαγεῖν verb aorist active infinitive from ἐσθίω (I eat) "to eat"