N2 · Structured courses

Koto Dakara: Knowing How...Is

"Knowing how X is, I predict Y"—based on familiarity. This lesson combines form, context, examples, common mistakes, and practice so you can use the pattern in real communication.

12 minNihongo Hub Editorial TeamPublished 2026-06-06Updated 2026-06-06

Learning objectives

  • Lesson goals: "Knowing how X is, I predict Y"—based on familiarity.
  • Form and connection: [Nounの/Plain form] ことだから
  • Nuance in real use: ことだから represents trust based on familiarity—I know you, so this is my inference.

Form and connection

[Nounの/Plain form] ことだから

Core Explanation

"Knowing how X is, I predict Y"—based on familiarity.

Cultural Note

ことだから represents trust based on familiarity—I know you, so this is my inference.

Practical examples

Knowing him, it'll be fine.
Knowing Tanaka-san, he's probably already prepared.

Common pitfalls

Build the base form before adding the pattern

Complete the required conjugation first. Do not keep polite and plain endings at the same time.

Match politeness to the situation

The examples are reliable starting points; relationships and context can still change the most natural wording.

Practice and answers

1. Write the connection formula for this lesson.
Show answer[Nounの/Plain form] ことだから
2. Explain the meaning of the first example.
Show answerKnowing him, it'll be fine.
3. Rewrite the final example using this lesson pattern.
Show answer田中たなかさんのことだからもう準備じゅんびできているでしょう。 ([Nounの/Plain form] ことだから)

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