[details=“English Translation”]Don’t shut your eyes.[/details] no cierres los ojos. or No cierren los ojos.
Don’t shut your eyes.
No cierres log ojos should be correct for the tu form
‘Cierres’ should be accepted as a correct answer, but isn’t.
This is just the way Clozemaster works: only one correct answer per cloze. That said, there is a feature called “Alternative answers”, but that seems to be confusing to most users when it kicks in (it changes your alternative answer to the official one after submission). I would suggest you use the “Hint” field to indicate the number and desired degree of formality (in this case: “ustedes”), so you can get it right next time.