Questions + Explanations Combined

How do you ask “why” politely with explanation?

どうして〜んですか？

Example

どうして遅れたんですか？ = Why were you late? (asking for explanation)

How to answer “why” politely

Verb/Adj + んです / から

Example

寝坊したんです = I overslept

How to ask “what happened?”

どうしたんですか？ = What happened? / What’s wrong?

How to give reason for past action

Verb past plain + んです

Example

食べすぎたんです = The reason is I ate too much

How to ask permission with reasoning

〜てもいいですか？ + 〜んです

Example

窓を開けてもいいですか？換気したいんです = Can I open the window? I want to ventilate

How to ask “how come?” casually

なんで〜の？ (informal)

Example

なんで来なかったの？ = How come you didn’t come?

How to respond casually

Verb plain + んだ / から

Example

忙しかったんだ = Because I was busy

How to explain feelings politely

Adj + んです

Example

嬉しいんです = The reason I’m happy is…

How to combine with か for question

Verb/Adj + んですか？

Example

見たんですか？ = Did you see it? / Is that what happened?