に->には / で->では etc


My question is kinda simple (I hope).

When somebody asks you, for example:

> 学生りょうにＴＶがありますか。

Can you answer:

> 台所 **には** ありますが、部屋 **には** ありません。

Or do you use:

> 台所 **に** ありますが、部屋 **には** ありません。

Can you also explain why that is, because I'm a little bit confused. Does the
same thing happen with で->では, へ->へは?




Both work fine, but the focus of the answer would be different.

> 台所にありますが、部屋にはありません。

I think this answer would be more "direct". The question is "Is there a TV in
the dorm?". A direct answer for this question would be "はい、テレビ **は**
台所にあります。", or simply "台所にあります。" with テレビ as the implied topic. After directly
answering the question, 部屋にはありません follows, which is an optional piece of
information.

> 台所にはありますが、部屋にはありません。

This answer sounds like you have already noticed that the questioner actually
wants a TV in his personal room. By adding the contrastive-wa in the first
half of the sentence, you signal that "there is a TV in the kitchen, but
that's probably not what you want". As a consequence, (テレビは)部屋にはありません gets
more focused.

More simply put, 台所にあります sufficiently works as a straight answer to the
question, whereas 台所に **は** あります sounds like "Yes, there is, _at least_ in the
kitchen".

Note that those explicit は after 台所に/部屋に are all contrastive-wa. The implied
topic is always テレビ(は) throughout the conversation. In different contexts, は
directly after ～に can safely work as a topic marker. See: [は、には、に。。。what is
the difference between them?](https://japanese.stackexchange.com/q/36908/5010)

