Deux semaines
Huit semaines. Please not that all numbers must be written out in French.
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les semaines
trois semaines
Not exactly see you in a few weeks but, à bientôt means see you soon. Vous voir en quelques semaines, I believe means see you in a few weeks. You can say Salut or au revoir to say goodbye.
It depends what you want to say. For example, if you want to say there's three weeks left before Christmas, say "Il reste trois semaines"
2 weeks
Je suis allé pendant deux semaines
Vacation, in French “Les Vacances” (always plural), is at the heart of the French culture. With 5 weeks of paid vacation for French employees, and a total of 16 weeks of vacation for French school students, France sure values her holidays.
March 2 is "le deux mars" in French.
the germans, for about 3 weeks
id say 2 weeks or 2 and a half weeks