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JLPT N5Copula

です / だ(desu / da) — The Declarative Copula

The Japanese equivalent of 'is/am/are' — the copula. It links the subject to a noun or na-adjective to form a complete predicate. です is polite; だ is plain/casual.

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Free lessonUNIT 3 · COPULA

Structure · 形

[Noun/na-Adj] + です (polite) | [Noun/na-Adj] + だ (plain)

Examples · 例文

  • これは辞書です。

    Kore wa jisho desu.

    This is a dictionary.

    これ (this) = 辞書 (dictionary) + です

  • 彼は親切な人だ。

    Kare wa shinsetsu na hito da.

    He is a kind person.

    だ = plain/casual copula declaration

  • 学生じゃありません。

    Gakusei ja arimasen.

    I am not a student.

    じゃありません = polite negative of です

Usage notes · 注意

  • Key Distinction: The copula does NOT mark physical existence (that is the job of いる/ある). It asserts identity or a property (A is B).
  • i-Adjective Rule: With true い-adjectives, です is only a politeness marker (寒いです). Because い-adjectives are already complete predicates, adding だ to them is ungrammatical (寒いだ is wrong; casual is just 寒い).

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones です is tested against.

vsいる / ある (existence)

です/だ equates two things ('A is B', identity); いる/ある state that something physically exists or is present ('there is / I have'). '猫です' = it is a cat; '猫がいます' = there is a cat.

vsい-adjective predicate

な-adjectives and nouns need だ/です to become a predicate (元気だ); い-adjectives are self-standing predicates and take です only for politeness, never だ (寒いです / 寒い, never 寒いだ).

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