「〜べきだ」- Should/Must

Explanation

「〜べきだ」 is a Japanese grammatical structure used to express obligation, duty, or advice, meaning "should" or "must." It is typically used to convey that the speaker believes something is correct or necessary.

Grammar Pattern

Grammar Point	Connection	Explanation
Verb Dictionary Form + べきだ	Verb Dictionary Form	Expresses obligation, duty, or advice, equivalent to "should."
Noun + である + べきだ	Noun + である	Used to indicate that something should possess a certain state or quality.

Basic Usage

Connection

• Verb Dictionary Form + べきだ
• Noun + である + べきだ

Meaning

• Expresses obligation, duty, or advice: "should" or "must."

Examples

• 早はやく寝ねるべきだ。
• Hayaku neru beki da.
• You should go to bed early.
  

• 学生がくせいは勉強べんきょうするべきだ。
• Gakusei wa benkyou suru beki da.
• Students should study hard.
  

• 彼かれは正直しょうじきであるべきだ。
• Kare wa shoujiki de aru beki da.
• He should be honest.
  

• 環境かんきょうを守まもるべきだ。
• Kankyou o mamoru beki da.
• We should protect the environment.
  

Comparison and Differences

Although both 「〜べきだ」 and 「〜なければならない」 express "should" or "must," they differ in tone and usage.

Grammar Point	Tone	Usage Context
〜べきだ	More subjective, expressing advice or obligation	Daily conversations, suggestions
〜なければならない	More objective, expressing necessity or obligation	Formal situations, rules

Examples:

• 早はやく寝ねるべきだ。
• Hayaku neru beki da.
• You should go to bed early.
  

• 早はやく寝ねなければならない。
• Hayaku nenakereba naranai.
• You must go to bed early.
  

Deep Dive

「〜べきだ」 is primarily used to express the speaker's subjective judgment or advice, with a relatively mild tone. It is commonly used in daily conversations to convey opinions or suggestions. In contrast, 「〜なければならない」 emphasizes objective necessity or obligation and is often used in formal contexts or rules.

Summary

「〜べきだ」 is a Japanese grammatical structure used to express obligation, duty, or advice, meaning "should." Mastering this pattern will help you better express your opinions and suggestions in both daily conversations and formal situations.