"Šestnáctá hodina byla opravdu důležitá."

Translation: The sixteenth hour was really important.

[JessicaYoung3]

I translated it as the sixteenth hour was very important how is this not a proper translation for the english?

[tatka_]

really = opravdu, skutečně

very = hodně, velmi

[elephantenlein]

May one use indeed here in place of really?

[VladaFu]

I added "was important indeed.". If you wanted other phrasing, please say it explicitly.

[EilatBenEl]

Could this sentence be also translated as "The sixteenth CLASS was really important"?

[VladaFu]

Lesson is accepted. Does class mean the same?

[EilatBenEl]

That's what I meant, actually. (I'm not such an expert in English, so "lesson" would do fine for me...) Thanks!

[butterfly604479]

Class can definitely be used in the same way as lesson in UK English. "It was my fourth class of the day."

[Gingencingen]

I wrote "The sixth hour..." (wrong, I know) but it was accepted as though I had only made a typo and corrected it to "The 1sixth hour..." (yes, with that number 1).

[VladaFu]

That is probably caused by the Duolingo automatic process that converts some numbers to words.