connective N2 common casualpolitewritten

〜ことだから — because it's ~ (knowing them)

〜ことだから・ことだから

Builds on こと

Meaning

since it's ~ / knowing ~ as we do, ~ — bases a confident prediction on someone's well-known character or habits

Key sentence

彼かれのことだから、また遅刻ちこくするだろう。

Knowing him, he'll probably be late again.

Formation

Attaches to	Form	Example
Noun (usually a person) + の	N + のことだから	あの先生せんせいのことだから / 真面目まじめな彼女かのじょのことだから

When: The subject is almost always a specific person (or group) whose character the speaker and listener both know; the second clause is a prediction that follows from that character.

Examples

几帳面きちょうめんな母ははのことだから、もう準備じゅんびは済すんでいるはずだ。

Knowing how meticulous my mother is, she's surely finished preparing already.

約束やくそくを守まもる彼かれのことだから、きっと来くるよ。

Since he always keeps his word, he'll definitely come.

Easily confused with

ことからことだから predicts from a person's known nature ('knowing her, she'll have done it'). ことから infers from an observed fact ('from the broken window, a burglar got in'). Different grounds: character vs evidence.

See 〜ことだから in real sentences

Jengo shows 〜ことだから the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.

Study it in Jengo

← Back to the grammar tree