Can someone explain why が is used here to ask a question, instead of か? If it
is to be more polite, can both be used interchangeably?

Situation: A man is ordering something at a burger shop.

Conversation:

> 男の人: すみません、スペシャルバーガーのセットをください。
>
> 店員: はい、ポテトかサラダがつきます _ **が**_ 。
>
> 男の人: サラダをお願いします。
CC BY-SA 4.0
2022-07-27T05:07:41.223
95569
2022-07-27T10:15:04.920
2022-07-27T10:12:58.463
9831
51952
question
questions
Asking questions using が?
This が is not a replacement of か. You cannot use か in the first place;
ポテトかサラダがつきますか ("Does it come with either fries or salad?") doesn't make sense
as a question from the clerk.

This が is the が which you probably remember as "but". In this sentence, が is
there to provide background information, and the actual question (どちらにしますか,
"Which do you like?") has been omitted.

  * [けど usage in ”魔石灯”がいい例だけど、”魔石”は…](https://japanese.stackexchange.com/q/32824/5010)
  * [が function in this sentence?](https://japanese.stackexchange.com/q/72494/5010)
  * [けれども as a neutral connector](https://japanese.stackexchange.com/q/19155/5010)

> はい、ポテトかサラダがつきますが（、どちらにしますか）。  
>  Okay. It comes with fries or salad, so...(which do you like?)

In Japanese, it's common to omit the final part of a sentence if it can be
inferred. If a sentence ends with "が?" or "けど?", something like "what do you
say/think?" or "what does it matter?" is often the omitted question. Similar
examples:

  * 明日は日曜日ですが？  
But it's Sunday tomorrow, are you sure?

  * はい、フランス語は話せますが？  
Yes, I can speak French, but why do you ask?
CC BY-SA 4.0
2022-07-27T05:27:21.003
95570
2022-07-27T10:15:04.920
2022-07-27T10:15:04.920
9831
5010
95569
answer