〜べき

Should/ought to

Level 4Sounds Like beki

〜べき is used to state that an action is the proper, right, or expected thing to do based on common sense, ethics, or duty. It is stronger and more objective than 'should' in English.

How It Works

〜べき（べき）functions as a pre-noun adjectival or a sentence-ending predicate when followed by だ or です. It carries a nuance of 'it is only natural that one does X' or 'it is one's duty to do X.'

1. Formation:

  • Verbs: [Dictionary Form] + べき (e.g., 行くべき、食べるべき).
  • Special Case (する): Both するべき and すべき are correct, though すべき is more traditional and formal.
  • い-Adjectives: Use the 'ku-form' + あるべき (e.g., 美しくあるべき - should be beautiful).
  • な-Adjectives: Use [Stem] + であるべき (e.g., 静かであるべき - should be quiet).
  • Nouns: Use であるべき (e.g., プロであるべき - should be a professional).

2. Tense and Negation:

  • Past (Should have): 〜べきだった. This often expresses regret.
  • Negative (Should not): 〜べきではない. In casual speech, 〜べきじゃない is very common. Note that you do not attach べき to a negative verb; the negation happens at the end.

3. Usage Nuance:
Because it sounds authoritative and objective, using it toward a superior (like a boss or teacher) can sound like you are lecturing them on their morals. In those cases, 〜ほうがいい is much safer.

Examples (6)

  1. 約束は守るべきだ。

    Promises should be kept.

    Word by Word: Promise (topic) keep should is.

    This expresses a general moral principle that applies to everyone.

  2. プロであるべきなら、もっと責任を持つべきだ。

    If you are to be a professional, you should take more responsibility.

    Word by Word: Professional be-should if, more responsibility (object) have should.

    This demonstrates how to use a noun with であるべき to describe an ideal state or duty.

  3. もっと早く家を出るべきだった。

    I should have left the house earlier.

    Word by Word: More early house (object) leave should was.

    Using the past tense べきだった expresses personal regret about a logical necessity that wasn't met.

  4. 学生はもっと勉強するべきです。

    Students ought to study more.

    Word by Word: Students (topic) more study should-do is.

    This uses the するべき form of する to describe the expected duty of someone in a specific role (a student).

  5. そんなひどいことは言うべきではない。

    You shouldn't say such terrible things.

    Word by Word: That kind of terrible thing (topic) say should not is.

    The negative form べきではない indicates that an action is socially or morally unacceptable.

  6. あんなにたくさん食べるべきじゃないよ。

    You shouldn't eat that much.

    Word by Word: That-much a-lot eat should-not-is (particle).

    This uses the colloquial negative form べきじゃない, which is common in spoken Japanese.

Common Mistakes

  • Attaching べき to the negative form of a verb.

    行かないべきだ。
    行くべきではない。

    In Japanese, you don't say 'should [not go]'; you say '[going] is not the thing that should be done.' Always use the dictionary form + べきではない.

  • Using べき for physical needs or simple desires.

    トイレに行くべきだ。
    トイレに行かなければならない。

    〜べき is for moral or logical 'oughts.' For physical necessities like going to the bathroom, use 〜なければならない.

How It Connects

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〜べきLevel 4Should/ought to

Learn This First

The pattern 〜べき (should/ought to) is used to express a moral or logical obligation. To use it correctly, learners must know how to identify the dictionary form of verbs across different verb groups and how to terminate the sentence using the copula. It is also helpful to understand more basic ways of giving advice to distinguish the nuance of this pattern.

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