Reason
This article introduces two particles that indicate reason, から and ので.
Kara (から)
To give a reason for something, use から (kara) either after the plain form of the verb or an -i adjective. After a -na adjective, use だ から (da kara).
新幹線で行ったから、時間があまりかかりませんでした。
Shinkansen de itta kara, jikan ga amari kakarimasen deshita.
We went by Shinkansen, so it didn't take very long.
質問がまだ多いから、もう一度説明しましょう。
Shitsumon ga mada ooi kara, mou ichido setsumei shimashou.
There are still a lot of questions, so let me explain again.
Node (の で)
The particle ので (node) translates to because. It can be shortened to んで (n'de) in casual speach.
窓を閉めてもかまいませんか。少し風邪気味なもんですので。
Mado o shimete mo kamaimasen ka. Sukoshi kazegimi na mon desu no de.
Would you mind if I shut the window? I have a slight cold.
遅くなってすいません、やる事がたくさんあったもので。
Osoku natte suimasen, yaru koto ga takusan atta mo no de.
I'm sorry I am late, but there's been a lot of work to do.
通していただけますか。飛行機が出ちゃいますので。
Tooshite itadakemasu ka. Hikouki ga decha imasu no de.
May I sneak in? My flight is leaving soon.
1日中働いた後なので、彼らはかなり疲れていた。
Ichinichijuu hataraita ato na no de, karera wa kanari tsukarete ita.
They were pretty tired after having worked all day.