"We cooked lunch."
Translation:Εμείς μαγειρέψαμε μεσημεριανό.
Well I would have expected that to be implied, as you're cooking today's lunch, so it is "the" lunch, not "a" lunch, i.e. any indeterminate lunch, and usually Greek seems to use the definite article where it is often left out in English (unlike the indefinite article, where it seems to be the other way round).
For example, I translated an exercise today in the form of "scientists do something or other" (I forget the detail), and I translated with no article, but was corrected to "οι επιστήμονας..."
Yes, the definite article is needed in many cases, but in this case using it would give emphasis that it is the Lunch that we cooked and not something else, and in that case in English we would say "We cooked the lunch", no? I think that the only difference between the uses of the definite article in Greek and in English is the fact that in Greek, it is used for general meanings. Οι επιστήμονες σε όλο τον κόσμο=Scientists all over the world.
I et quite irritated by the use of εμείς and subject pronouns in general, especially αυτή for 'she' and αυτός for 'he', except when emphasized. The correct English translation of this sentence is rather 'It was us who cooked lunch', or 'WEEE cooked lunch (not you, if you can get it into your stupid heads)!'
The correct translation is We cooked lunch (as in not you) or We cooked lunch (what did you do?). It was us who cooked lunch is even more emphatic and in Greek it is Ήμασταν εμείς που μαγειρέψαμε! So, "we cooked lunch" is correct because there is no way in written speech to show the intonation.