how do I use ～んです with a noun?


I'm learning to use ～んです and according to my class notes, when used with a
noun it should be conjugated like " noun + な + んです".

This is just a random example but I want to make sure I'm using this properly.

Let's say someone asked: "それは どうですか。"  
Is this a correct response: "これは ねこなんです。"

Also, if you have a more realistic example of when you would use ～んです with a
noun, I'd love to see it.

Lastly, I would like to see an explanation on how to conjugate verbs with ～んです
as well. I'm still a bit confused about it and my textbook is not clearing it
up for me.

Thanks in advance!! :)




> 「～～な（の/ん）です/だ」 (More informal with 「ん」)

is an _**explanatory**_ expression. It is different from (and more nuanced
than) a simple declarative statement describing what/how something is, which
takes the form:

> 「～～です/だ」

**If there is a cat in front of you that looks unmistakably like a cat, you
will say** :

> 「これはネコです。」

In fact, (unless you want to practice speaking Japanese,) you might not even
say that because it is so obviously a cat. It could not be anything else (any
other kind of animal). The point is that it would still make sense to say
that.

What you will _**never**_ say, however, in this situation is:

> 「これはネコなんです。」 ≒ "Actually, this is a cat.", "Believe it or not, this is a
> cat.", etc.

That will sound nonsensical, won't it?. I hear this misuse among J-learners on
Japanese TV and Youtube **all the time**. In fact, I had been waiting for
someone to ask about this here for quite some time.

So, **when can we say 「これはネコなんです。」, the explanatory version**?

You can say it when you have a cat that does not look like a cat -- most
likely, it looks like another kind of animal.

> Guy: 「それ、何{なん}の動物{どうぶつ}？キツネ？」 "What's that animal? A fox?"

> You: 「これ、ネコなんです（よ）。そう見{み}えないけど。」 "It's a cat! Doesn't look like one,
> though."

Hope my explanation was clear enough.

With verbs, you can just add 「のです/んです」 to the dictionary form or the past
tense form. No other forms will work.

Below is the image of Japan's first disposable camera named 「写{うつ}ルンです」 (see
lower left corner for name). The name implies something like "It actually
takes (good) pictures despite its cheap look." In other words, it is
**explanatory**.

[![enter image description
here](https://i.stack.imgur.com/Ju9B0.jpg)](https://i.stack.imgur.com/Ju9B0.jpg)  
(source:
[naver.jp](https://rr.img.naver.jp/mig?src=http%3A%2F%2Fimgcc.naver.jp%2Fkaze%2Fmission%2FUSER%2F20150320%2F25%2F2592725%2F8%2F300x233x12ee3d853677a1c2604eddd3.jpg%2F300%2F600&twidth=300&theight=600&qlt=80&res_format=jpg&op=r))

