Explanation of things using んです

In this lesson, I will introduce you the expression using んです, which is used to explain things.
んです follows plain form of verbs, adjectives, and nouns.

<Example Sentences>
In response to the utterance, "You look tanned!"
ハワイ　に　いったんです。
I went to Hawaii.
*いった is past tense plain forms of いく, go
*んです explains the reason why you look tanned.

どうして　きのう　パーティ　に　こなかったんです　か。
Why didn't you come to the party yesterday?
きのう　は　おきゃくさん　と　うちあわせ　が　あったんです。
I had a meeting with a customer yesterday.

If you were Chinese, and someone talk to you in Japanese, you can say,
ちゅうごくじんなんです。
I am Chinese.

In response to your neighbor's utterance, "Your dog runs fast!",
げんきなんです。
He is healthy.

どうしたんですか。
What happened?
あたま　が　いたいんです。
I have a headache.

References:
Introduction to Plain Forms
https://anchor.fm/yuya-sato/episodes/Introduction-to-Plain-Forms-enp0g3

Plain Forms in Past Tense
https://anchor.fm/yuya-sato/episodes/Plain-Forms-in-Past-Tense-eoe8fp

Describing a Person's Feature
https://anchor.fm/yuya-sato/episodes/Describing-a-Persons-Feature-ennovs

Adjectives
https://anchor.fm/yuya-sato/episodes/Adjectives-en9o8v

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