"You ate only one cookie; are you sick?"

Translation: Tu n'as mangé qu'un biscuit, es-tu malade ?

[MichelLemoine123]

"Tu n'as mangé qu'un seul biscuit, es-tu malade ?" is also accepted.

[doublelingot]

Tu as seulement mangé un biscuit, tu es malade ?

[effyleven]

You have eaten but one biscuit... etc?

[fleursmortes]

This phrase is equally correct using vous, n'est-ce pas? please include it.

[GraemeSarg]

It seems a bit cheeky/impertinent for somebody whom you vouvoyer, and not very plausible as a plural "you".

IMHO, "tu" is the only sufficiently plausible translation.

[fleursmortes]

agreed, thanks for your perspective :)

[zanitti]

"Vous n'avez mangé qu'un biscuit, êtes-vous malade ?" This phrase should be accetped.

[Atervanda]

It is.

[Doggydoodo1]

Not in the spirit of learning “ne...que” but is “ tu as mangé un seul biscuit, es-tu malade ?” actually incorrect? I’m much more likely to use this type of construction during my visits to France.

[Student179]

It should be "Tu as seulement mangé un biscuit, es-tu malade?". Duo does accept that construction.

[tigerstef]

Que and un don't need to be contracted here?