Ready to explain yourself (and ask why)? This lesson helps you ask for reasons and give clear answers in natural polite Japanese. Have fun — reasons are great conversation fuel!
Level B1: In this lesson you'll practice common ways to ask why (どうして／なんで) and natural patterns to give reasons (〜から、〜ので、〜からです). We'll use polite spoken Japanese to ask about decisions, wants, and past actions — and respond clearly. CEFR-aligned, practical, and conversation-ready.
After this lesson you'll be able to:
Ask why someone did or decided something using どうして and なんで (Dōshite / Nande).
Say short reasons with 〜からです, 〜から、〜ました and explain decisions with ことにした.
Use 〜ので to give context before your action and understand polite explanations.
Ready? Let's go!
When you tap play on phrases, we track your progress through this lesson.
1. Reading + Listening Practice
Hear core phrases, repeat aloud.
どうして___んですか。
Dōshite ___ n desu ka.
Why did you ___?
Meaning: Why did you ___?
When to use: Use this polite question to ask why someone did something in the past. Put the past plain form in the blank (例：行ったんですか).
Tip: Beginner mistake: forgetting to use the past plain form (来た vs 来なかった). Put the past form in the blank for past actions.
どうして来なかったんですか。
Dōshite konakatta n desu ka.
Why didn't you come?
どうして遅れたんですか。
Dōshite okureta n desu ka.
Why were you late?
どうして___たいんですか。
Dōshite ___ tai n desu ka.
Why do you want to ___?
Meaning: Why do you want to ___?
When to use: Ask the reason someone wants to do something now or in the future. Put a verb base + たい in the blank (例：行きたい).
どうして日本へ行きたいんですか。
Dōshite Nihon e ikitai n desu ka.
Why do you want to go to Japan?
どうしてその本を読みたいんですか。
Dōshite sono hon o yomitai n desu ka.
Why do you want to read that book?
___のはどうしてですか。
___ no wa dōshite desu ka.
What's the reason for ___?
Meaning: What's the reason for ___?
When to use: Use this polite phrase to ask for the reason for a situation or action. Put a short clause or verb phrase in the blank (例：遅れたのはどうしてですか).
休んだのはどうしてですか。
Yasunda no wa dōshite desu ka.
What's the reason you took a day off?
提出が遅れたのはどうしてですか。
Teishutsu ga okureta no wa dōshite desu ka.
Why was the submission late?
なんで___んですか。
Nande ___ n desu ka.
How come ___?
Meaning: How come ___?
When to use: A more casual way to ask why something happened. Put a plain form clause in the blank. Use どうして for more formal speech.
Tip: Be careful: なんで is casual. In polite situations prefer どうして.
なんで来なかったんですか。
Nande konakatta n desu ka.
How come you didn't come?
なんでそんなに高いんですか。
Nande sonna ni takai n desu ka.
How come it's that expensive?
___から、やりました。
___ kara, yarimashita.
I did it because ___.
Meaning: I did it because ___.
When to use: Put the reason clause before から and follow with やりました to say you did something because of that reason.
宿題があったから、先にやりました。
Shukudai ga atta kara, saki ni yarimashita.
I had homework, so I did it first.
説明が分かりにくかったから、もう一度やりました。
Setsumei ga wakari nikukatta kara, mō ichido yarimashita.
Because the explanation was hard to follow, I did it again.
___から、それを選びました。
___ kara, sore o erabimashita.
I chose it because ___.
Meaning: I chose it because ___.
When to use: Use this to explain why you chose something. Put the reason clause before から; それ refers to the item mentioned earlier.
値段が安いから、それを選びました。
Nedan ga yasui kara, sore o erabimashita.
I chose it because the price was low.
色が好きだったから、それを選びました。
Iro ga suki datta kara, sore o erabimashita.
I chose it because I liked the color.
___からです。
___ kara desu.
It's because ___.
Meaning: It's because ___.
When to use: A short, natural way to answer 'why' with a brief reason. Put a reason clause in the blank.
疲れたからです。
Tsukareta kara desu.
It's because I'm tired.
忙しかったからです。
Isogashikatta kara desu.
It's because I was busy.
一番の理由は___です。
Ichiban no riyū wa ___ desu.
The main reason is ___.
Meaning: The main reason is ___.
When to use: Use this slightly formal phrase to state the primary reason. Put a noun or short phrase in the blank (or a short clause).
一番の理由は時間がないです。
Ichiban no riyū wa jikan ga nai desu.
The main reason is that there's no time.
一番の理由は近いことです。
Ichiban no riyū wa chikai koto desu.
The main reason is that it's close.
___から、できませんでした。
___ kara, dekimasen deshita.
I couldn't because ___.
Meaning: I couldn't because ___.
When to use: Give a negative reason. Put the reason clause before から and finish with できませんでした or another past negative verb.
体調が悪かったから、できませんでした。
Taichō ga warukatta kara, dekimasen deshita.
I couldn't because I wasn't feeling well.
お金が足りなかったから、買えませんでした。
Okane ga tarinakatta kara, kaemasen deshita.
I couldn't buy it because I didn't have enough money.
___ので、私は___。
___ node, watashi wa ___.
Since ___, I ___.
Meaning: Since ___, I ___.
When to use: Put the reason or context before ので, then say what you did. 私は can be included for emphasis but is often omitted in speech.
Tip: Note: ので feels softer/less direct than から. Use ので to give background politely.
雨が降っていたので、私は家にいました。
Ame ga futte ita node, watashi wa ie ni imashita.
Since it was raining, I stayed at home.
仕事が忙しかったので、私は行けませんでした。
Shigoto ga isogashikatta node, watashi wa ikemasen deshita.
Since work was busy, I couldn't go.
どうして___ことにしたんですか。
Dōshite ___ koto ni shitan desu ka.
What made you decide to ___?
Meaning: What made you decide to ___?
When to use: Ask about someone's motivation for a decision. Put a verb plain form in the blank (例：日本語を勉強することにした).
どうして日本語を勉強することにしたんですか。
Dōshite Nihongo o benkyō suru koto ni shitan desu ka.
Why did you decide to study Japanese?
どうして犬を飼うことにしたんですか。
Dōshite inu o kau koto ni shita n desu ka.
Why did you decide to get a dog?
どうして___のか、説明してもらえますか。
Dōshite ___ no ka, setsumei shite moraemasu ka.
Could you explain why ___?
Meaning: Could you explain why ___?
When to use: A polite request for an explanation. Put a plain-form clause in the blank. More formal: 説明していただけますか。
どうして計画を変えたのか、説明してもらえますか。
Dōshite keikaku o kaeta no ka, setsumei shite moraemasu ka.
Could you explain why you changed the plan?
どうして遅刻したのか、説明してもらえますか。
Dōshite chikoku shita no ka, setsumei shite moraemasu ka.
Could you explain why you were late?
___のには、理由がありますか。
___ no ni wa, riyū ga arimasu ka.
Is there a reason why ___?
Meaning: Is there a reason why ___?
When to use: Ask whether there is a reason for something. Put a plain-form clause in the blank (例：やめたのには、理由がありますか).
仕事を辞めたのには、理由がありますか。
Shigoto o yameta no ni wa, riyū ga arimasu ka.
Is there a reason you quit your job?
彼と別れたのには、理由がありますか。
Kare to wakareta no ni wa, riyū ga arimasu ka.
Is there a reason you broke up with him?
2. Conversational Listening Practice
Hear phrases in a real mini-conversation.
Anna asks why David decided to study and David explains with reasons.
What reason does David give for his decision?
Anna
どうして日本語を勉強することにしたんですか。
Dōshite Nihongo o benkyō suru koto ni shitan desu ka.
Why did you decide to study Japanese?
David
仕事で日本に行くかもしれないからです。
Shigoto de Nihon ni iku kamoshirenai kara desu.
It's because I might go to Japan for work.
Anna
なんで仕事で行くかもしれないんですか。
Nande shigoto de iku kamoshirenai n desu ka.
How come you might go for work?
David
会社が新しいプロジェクトを始めるので、私が手伝うことになったんです。
Kaisha ga atarashii purojekuto o hajimeru node, watashi ga tetsudau koto ni natta n desu.
Because the company is starting a new project, I was asked to help.
3. Guided Practice
Quizzes and matching to lock in meaning.
Which Japanese phrase asks, 'What made you decide to study Japanese?'
Which phrase politely asks 'What's the reason for being late?'
Which one is the casual 'How come ___?' pattern?
Which sentence says 'I couldn't because ___'?
Tanaka didn't come yesterday. Why didn't he come?
田中さんは昨日来なかった。どうして___？
Tanaka-san wa kinō konakatta. Dōshite ___?
I couldn't go today. I couldn't because I had a fever.
今日は行けなかった。___から、できませんでした。
Kyō wa ikenakatta. ___ kara, dekimasen deshita.
To work in Japan, why did you decide to study Japanese?
日本で仕事をするために、どうして___ことにしたんですか。
Nihon de shigoto o suru tame ni, dōshite ___ koto ni shita n desu ka.
Match the core phrases
Match the extra phrases
4. Speaking Practice
Say phrases yourself (mic/recording).
Recording stays on your device only. Check speech uses your browser's speech tools when available.
