日本語 132      「ん です」as the Explanatory Mode

 

V or Adj in the plain form (affirmative or negative) + ん です = is colloquial for the  の です form. 

いそがしいんです I'm busy.

時間がないんです=I've got no time

 

Since we add these to Verbs and Adjectives—either affirmative or negative—we are “Extending the Predicate," the basic function of which is to appeal to the assumed common understanding or knowledge shared between the speaker and the listener.  Even if the common knowledge does not exist, it describes the knowledge as if it were shared hence encouraging a sense of emotional rapport.

 

Also, "~ n desu" is used quite often in conversation, though it might be difficult to use correctly for beginners. It has an explanatory or confirmatory function. The difference between "~masu" (a normal ending of the verb) and "~n desu" is very subtle, therefore it is very hard to translate the nuance.

"Why" questions are often asked with this expression, because they are asking for a reason or an explanation.

Doushite byouin ni iku n desu ka.
Haha ga byouki nan desu.

どうして病院にくんですか。
母が病気なんです。
Why are you going to the hospital?
Because my mother is sick.
Doushite tabenai n desu ka.
Onaka ga suite inai n desu.

どうして食べないんですか。
おなかがすいてないんです。
Why don't you eat?
Because I am not hungry.

from: http://japanese.about.com/od/Question-of-the-Week/fl/What-is-n-desu-which-is-sometimes-used-at-the-end-of-a-sentence.htm

 

More specifically, there are at least three related but distinct functions of this form of extended predicate:

 

1.     To signal that what precedes the ん です offers the reason or cause related to the issue at hand.

2.     To emphasize what precedes ん です .

3.     To present the request in a milder tone.  Hence it can be considered friendly and colloquial.  (from Senko Maynard, An Introduction to Japanese Grammar and Communication Strategies pp. 236-237.

 

If we have to add ん です to a Noun or a な-Adjective, we have to put the な  back in front of the ん です,  like

好き なん です=Because I like it;

びょうき なんです = Because she is sick.

 

 

We can also add what our textbook offers, i.e., that ん です is used to register surprise and also to ask for and to give EXPLANATIONS. Hence it is often used with "Why" questions, e.g.

 

どうして いかないん ですか。(How come you are not going?)

 

いそがしいん です。 (I am busy!)

 

どうして かわないん ですか。(How come you won't buy it?)

 

高いん ですよ! (It's expensive!)

 

We also say, by way of explanation, that X が あるんです=I have X or there is X

 

or ask the question 何か あるんですか?= Do you have something (to do)? See Nakama p. 312, Activity 2, 3

 

Note: 何+か=Something

 

どうして

1、いきませんか. Why won't you go to the ....First, put the question in the ん で from by convertingthe いきませんか form to  いかないん ですか

Then you answer with your explanation + ん です

としょかん  = どして としょかんへ いかないんですか

ビストロ

ポートランド

日本

えいが

 

2、たべまんせんか。

にく

やさい

さしみ

ピザ

あさごはん

 

3、のみませんか。

こうちゃ

コーヒー

ビール

スキー

ワイン

ミルク


ジュース

おちゃ

 

4、そうじをしませんか。

 

5、よみませんか。

ざっし

しんぶん

 

6、みませんか。

えいが

テレビ

DVD

 

More on the Plain form んです

That means when speaking, therefore in Conversation, native Japanese normally use 「~んです」 instead of 「~のです」.

This sentence pattern is used when the speaker explains to the listener the reason for his own words and deeds, while an interrogative sentence in this form is used when the speaker is asking for an explanation of what the listener has done.

Example
-------

A: あなたはビールを飲まないんですか
anata wa bi-ru wo nomanai n desu ka
Meaning: Don't you drink beer?

B: ええ、きらいなんです
ee, kirai na n desu
Meaning: No, I don't like it.

To use this sentence pattern "n desu," something should be obvious, something you have seen or heard. For the above example, it's obvious that the speaker noticed that the listener is not drinking beer and ask the question. And this sentence pattern always shows the speaker's curiosity or interest in the question.This ん です pattern can be in the PAST, too, e.g.

 

どうして いかなかったん ですか。Why didn't you go?

 

いそがしかったん です。

 

しゅくだいが あったんです。

 

時間が なかったんです。

 

どうして かわなかったんですか。Why didn't you buy it?

 

高かったんです。

 

お金が なかったんです。