どこ and なに in subject questions


> はい、こちらサービスセンターです。
>
> すみません。コンピューターが壊れてしまったんです。
>
> **どこ** が壊れたんですか。
>
> わかりません。

As far as I understand, the manager is asking what exactly has broken ( _which
part of the computer is broken?_ ). If we said 何が壊れたんですか in this situation,
would the answer be _the computer_?

When shall we use どこ and 何 in subject questions?




Yes, your assumptions are correct.

As 何 just means 'what', asking 'What is broken?' would be met with
incredulity, as you already told the rep that the computer is broken.

（～の）どこ in cases such as this these, means 'which part of'. In essence, part of
the subject is being omitted in the query from the rep. The full sentence
would be 「 **コンピューターのどこ** が壊れたんですか。」

This use of （～の）どこ is fairly ubiquitous for specifying the part or specific
location of something ('Where does it hurt?', 'Which section/area of the park
should we meet?', 'What don't you like about me?', etc.)




In this context it would be odd to ask 何が壊れたんですか？ because the answer would
obviously be コンピューターです

> **Customer:** My computer is broken.（コンピューターが壊れてしまったんです）
>
> **Service Tech:** What's broken?（何が壊れたんですか？）
>
> **Customer:** I just said it's my computer!（コンピューターだと言ったでしょ？）

A better response would be...

> **Service Tech:** How is it broken? _(What's wrong with it?)_

The way to ask this in Japanese is to use **どこが** 壊れたんですか？

  * **何が** 壊れたんですか？ → What (thing) is broken?
  * **どこが** 壊れたんですか？ → What _**(about the thing)**_ is broken?
  * **どのように** 壊れたんですか？ → How did (the thing) come to be broken?

You should use どこが when you want to know _" what part of"_ or _" in what way"_
some state came to be.

  * 何が悪いんですか？ → What's bad?
  * **どこが** 悪いんですか？ → What's bad _**about it**_?

--

  * 何が分からないの？ → What don't (you) understand?
  * **どこが** 分からないの？ → _**What part**_ don't (you) understand?

