Grammar › N5 · 06 Plain forms and te-form
だ: plain 'is' (copula)
N5 · 06 Plain forms and te-form
Plain-style 'to be' after nouns and na-adjectives.
Polite equivalent is です. Not used after i-adjectives (×高いだ). Becomes な before ので / のに / の.
Examples
これは私の本だ。
This is my book.
彼のお父さんは医者だ。
He is a doctor.