copula N5 essential casualwritten
〜は〜だ — topic-comment: X は Y だ
〜は〜だ
Meaning
- X is Y — the basic plain-form statement: は marks the topic, だ asserts what it is
Key sentence
これは本だ。
This is a book.
Formation
| Attaches to | Form | Example |
|---|---|---|
| Topic (noun) + は, Comment (noun / na-adj) + だ | X は Y だ | 彼は学生だ |
When: Plain style — used in casual speech and in written/neutral prose. For polite conversation use 〜は〜です.
Examples
今日は休みだ。
Today is a day off.
あの人は有名な歌手だ。
That person is a famous singer.
私の趣味は写真だ。
My hobby is photography.
When you can't use it
- だ does not attach to an i-adjective. Say 寒い (it's cold), never 寒いだ. だ closes only noun and na-adjective comments.
Easily confused with
See 〜は〜だ in real sentences
Jengo shows 〜は〜だ the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.
Study it in JengoSources Compiled with reference to A Dictionary of Basic Japanese Grammar.