～ので
because / since
～ので connects a reason to a result, like English “because” or “since”. The reason comes first, ので is attached to it, and the result follows.
Compared with から, ので sounds softer and more objective. It presents the reason as a natural fact rather than the speaker's personal claim. That makes it a polite, safe choice for excuses and requests.
1. Giving a reason
Attach ので to the plain form of a verb or い-adjective. In polite speech you can also attach it to the ます-form (例: 行きますので).
忙しいので、行けません。
“I can't go because I'm busy.”
- 忙しい（いそがしい）= busy
- ので = because
- 行けません（いけません）= can't go
2. なので after nouns and na-adjectives
After a noun or a na-adjective, ので needs な in between, giving なので.
雨なので、家にいます。
“Since it's raining, I'll stay home.”
- 雨（あめ）= rain
- なので = because it is (な + ので, used after nouns)
- 家（いえ）= home, house
- に = location marker
- います = will stay, am (to be, for people and animals)
How to form it
Plain form + ので / Noun・na-adjective + なので
- 忙しい（いそがしい）= busy → 忙しいので（いそがしいので）= because (I) am busy
- 行く（いく）= to go → 行くので（いくので）= because (I) am going
- 静か（しずか）= quiet → 静かなので（しずかなので）= because it is quiet
Key idea
～ので means “because”, presenting the reason as a gentle, natural fact. Remember the extra な after nouns and na-adjectives: 雨なので, 静かなので.
Other N5 grammar
Updated .