A conjunction meaning "so" or "therefore"; used to present a conclusion or result based on what was just said.
今日は雨が降っている。だから傘を持って行った。
It's raining today. So I took an umbrella.
彼は忙しい。だから返事が遅いんだ。
He's busy. That's why his replies are slow.
財布を忘れた。だから昼ごはんは買えなかった。
I forgot my wallet. Therefore I couldn't buy lunch.
An expression used at the start of a sentence to mean "like I said" or "I told you so" — often to remind or reproach the listener.
だから言ったでしょ、無理だって。
I told you, didn't I? It's impossible.
だから、もうやめなさい！
Seriously, stop it already!
だから見ろって言ったんだよ。
I told you to look (see), didn't I?