Questions & Answers about Utinam cantharus in fornace non frangatur!
Latin regularly uses the subjunctive after utinam to express a wish. The speaker is not saying that the cup actually breaks or does not break; the speaker is wishing that it not happen.
So:
- frangitur = it is broken / it breaks
- frangatur = may it be broken / may it break in a wish-clause
Frangatur is:
- 3rd person singular
- present subjunctive
- passive
- from frangere, meaning to break
The ending -tur shows that it is passive. The subjunctive vowel here is part of the present subjunctive formation.