"They went on holidays to France last year."
Translation:Ils sont allés en vacances en France l'an dernier.
The good one is : "Ils sont allés en vacances en France, l'an dernier". The use of the imparfait is not relevant because there is a date (l'an dernier), so it is not as if it was a general statement about what those people used to do in an undefined past.
What about my answer, is it at least accepted in oral speech? Ils sont allés en France pour vacances l'année dernière.
You missed the article: ils sont allés en France pour les vacances l'année dernière.
I used what I assumed to be the correct idiomatic structure: «Ils sont partis en vacances en France l'an dernier.» I do realize it would be literally translated as, "They left [for] vacation in France last year."
I am pleased, however, that I have finally grasped the difference between the use «l'an» and «l'année».
L'anné passé, ils sont allés en France pour les vacances
Is there a legitimate reason behind this being incorrect?
l'année passée is feminine.
"l'an dernier" or "l'année dernière" are more frequent in everyday conversations.
Would l'année passée be correct in this sentence, even though it wouldn't be used frequently when speaking?
Can you use "passer les vacances" for "went on vacation"? If not, why?
There is no movement in "passer" (ils ont passé les vacances chez eux/they spent the holidays at home)
I used "les fetes" to refer to the holidays, can anybody tell my why it would be wrong. I saw it as a valid translation to holidays by DL on a previous exercise.
"les fêtes" almost exclusively refers to the period between Christmas and New Eve.
"les vacances" can be at any time in the year, generally in the summer and when it is not in the summer, we use "les vacances de février", "les vacances de printemps"...