"Did you make dinner?"

Translation: Zrobiłyście obiad?

[RickardRicky]

I answered "Czy przygotowałes obiad?".

[Paranoix]

It is correct but for me it sounds weird. We use "zrobić" more often. And remember you can skip "czy".

[JerryMcCarthy99]

Hmmm. Multiple choice requires both "Zrobiłaś obiad?" and "Zrobiłeś kolację?" ?. Yet, elsewhere, "obiad" seems to be "lunch", and "kolacja" seems to be "dinner".

[Emwue]

There is really no clear cut distinction – dinner can be a second or third meal of the day, which translates respectively to „obiad” or „kolacja”, though obviously 'lunch' can also be „obiad”, just as much as 'supper' or 'tea' can be „kolacja”. Unfortunately, the dialectal differences in naming the meals are making a mess of it. ;)

[Makaronizm]

why not, "czy zjadłeś kolację?" ?

[Jellei]

Because the sentence mentions making, not eating. Your sentence is perfectly correct... it just doesn't mean what it was supposed to mean ;)