復習

Lesson 39 — て/で (原因げんいん) · ので

BOOK II · 初級 II

L39 · cause て/で/ので

FOR TEACHERS ≈35 min to teach · 19 slides · 8 checks 2 min a slide, 1.5 a check. An estimate, not a lesson plan.

Words with a dotted underline have meanings — tap one. So does the big word on every drill card.

REF て/で (原因げんいん) · ので ›

1. 〜て / 〜で — cause

TypeFormExample
verbて-form
い-adj
な-adj
noun
verb negative

Restriction: the main clause cannot be a request, invitation, command, or intention.

✕ → use から / ので.

Verbs and adjectives that pair naturally with て-cause

Emotion
Adjectives
Involuntary result

The cause clause describes something already settled, so it never contains 〜たい, ましょう, or a command.

2. 〜ので — reason (soft, objective)

Formation: plain form + ので; な-adj and noun take なので.

TypeFormExample
verbplain
い-adjplain
な-adj
noun

Polite-form ので (〜ますので) exists and is even more formal.

3. から vs ので

からので
subjective — asserts your reasoningobjective — presents it as natural circumstance
fine for strong claims, refusalssofter; better for excuses and requests to superiors

When apologizing or asking a favor of someone senior, ので is the safer choice — から can sound like you're arguing.

4. Three ways to give a reason

cause, no volition in the result
subjective reason, any result
soft objective reason, any result
Set expressions会話かいわ

Key vocabulary
生うまれます驚おどろきます喜よろこびますびっくりしますがっかりします安心あんしんします困こまります倒たおれます込こみます複雑ふくざつ大変たいへん残念ざんねん怖こわいうれしい悲かなしい寂さびしい事故じこ地震じしん火事かじ台風たいふう事件じけん操作そうさ説明せつめいおかげで
詳説 In depth — grammar notes ›

1. 〜て / 〜で — cause, stated plainly

The て-form already means "and then"; with the right pair of clauses it means "and because of that". The cause comes first, the consequence second.

TypeFormExample
verb
い-adj
な-adj
noun
verb negative

The big restriction: the second clause cannot be a request, an invitation, an order or a statement of intention. ✕ → ○. て-cause only reports things that happened to you.

Words that pair naturally with て-cause

The consequence is normally an involuntary reaction — a feeling, a state, an inability.

CategoryWords
feelings
trouble
inability
JapaneseEnglish
I'm happy I could see my family.
The road was jammed, so I missed my appointment.
My Japanese is poor and I'm embarrassed.
The trains stopped because of the earthquake.

A bare noun + で is the standard way to blame an event: , , , .

2. 〜ので — reason, soft and objective

ので presents the reason as an obvious fact rather than your personal argument, which is why it sounds polite and slightly apologetic. Perfect for excuses and requests.

TypeBefore ので
verbplain form:
い-adjplain form:
な-adj+ な:
noun+ な:
JapaneseEnglish
I have something to attend to, so I'll leave first.
My Japanese is still poor, so could you speak slowly?
I have a fever, so I'd like to take today off.

な-adjectives and nouns take な, not だ: ✕ · ○ · ○.

3. から vs ので

からので
feelmy reason, stateda circumstance we both accept
tonedirect, can sound pushysoft, polite
best forexplaining a decision, answering なぜexcuses, requests, apologies
before な-adj/noun
can stand alone as an answer
JapaneseReads as
I'm not going — I've no time. (blunt)
I'm afraid I can't go, as I've no time. (polite)

Answering a なぜ / どうして question, use . ので cannot end a sentence that way.

4. Three ways to give a reason

FormSecond clause may beRegister
only a fact, feeling or inabilityneutral, describes what happened
anything, including requestspolite, soft
anythingdirect, personal
Same idea, three ways
Error table
✕○Why
no request after て-cause
noun + な before ので
nouns take で
negative cause is なくて, not ないで
only から can close the answer
Try translating
EnglishJapanese
I was surprised to hear the news.
The trains stopped because of the typhoon.
I couldn't sleep because it was noisy.
I have an errand, so I'll be leaving first.
Could you speak slowly, as my Japanese is poor?
Why were you absent? — Because I had a fever.
練習 8 checks
Q1 negative cause

'The bus didn't come, so I was late.'

な
く
て
なくて = cause. ないで = manner/instead (L34)
Q2 cause verb

'I heard the news and was surprised.'

〜
て
て-form = cause, especially with emotion verbs
Q3 cause noun

'The building collapsed because of the earthquake.'

〜
で
noun + で = cause
Q4 cause い-adj

'The explanation was difficult so I don't understand.'

く
て
い-adj: くて = cause
Q5 restriction

Which is WRONG with 〜て as cause?

✕
て
て-cause can't precede requests/invitations/commands — use から/ので
Q6 reason verb

'I have an errand, so I'll excuse myself.' (polite, soft)

の
で
plain + ので = soft, objective reason
Q7 noun + ので

'Because it's Sunday, the roads are crowded.'

な
の
で
noun/な-adj → なので
Q8 nuance

から vs ので — which is softer and better toward a superior?

か
ら
・
の
で
ので = objective/soft; から = subjective/assertive

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みんなの日本語にほんご · Lesson 39