你们学校的校庆是什么时候？（翻译）

一般：when is the founding anniversary of your school?
标准：On which day was your school founded?(换位思考：知道哪天建校，自然就知道校庆是哪天了)
另外：when will your school celebrate its glorious founding?(加个glorious表示语气欢快)
精典：Can you tell me the exact date of your school's establishment?

When is your school's anniversary?

The anniversary ceremony of your school drops on which day?

那你想要什么样的答案呢？前面两个都挺好的啊~