Dans vs à
I had a French test in school the other day and when I got the results back today my teacher had marked J'ai joué le foot dans le parc (for I played football in the park) as incorrect because i had said dans le instead of au. If this is correct, could someone please explain to me when to use dans and when to use à.
It's hard to come up with hard-and-fast rules about prepositions (in any language, not just French). In this specific case, it's clear from Googling that most French people prefer "au parc" over "dans le parc", but there are exceptions, like "Il est allé jouer au foot dans le parc devant l’école" (http://anewyorkavectoi.com/2015/03/24/le-temps-retrouve/) or "[Quel est le] spot où l’on peut voir le président de la République jouer au foot dans le parc avec ses garçons de vestibule ?" (http://madame.lefigaro.fr/art-de-vivre/lelysee-backstage-171210-112753), so you could make the case that dans is acceptable here.
What's more problematic in your sentence is the omission of à after joué. Whenever you talk about playing a sport or a game in French, the à is obligatory: jouer au tennis, jouer aux échecs, etc.
Thanks for the help!
BTW I had written au foot in the exam, just forgot to put it here:)
I always mix up "en", "au", "dans" and "à"
I haven't figured out the pattern yet
"J'ai joué au foot dans le parc" and "J'ai joué au foot au parc" are both fine. I prefer the first version.
au parc = at the park / dans le parc = inside the park
I always try to remember that dans will usually equate to being inside of something.