Processing keyword: ～はずだ (〜hazu da)

Japanese Grammar Point: ～はずだ (〜hazu da)

1. Introduction

The grammar point ～はずだ (〜hazu da) is a common expression in Japanese used to express expectation or supposition based on reasoning or evidence. It conveys the speaker's belief that something should be a certain way due to logical reasons.

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2. Core Grammar Explanation

Meaning

• ～はずだ is used to express that something is expected to happen or should be true based on certain information or reasoning.
• It can be translated as "should be", "ought to be", or "supposed to be" in English.

Structure

The structure varies depending on the type of predicate:

Verb Form	Structure	Example
Verb (dictionary)	Verb + はずだ	行くはずだ
Verb (ない-form)	Verbない + はずだ	行かないはずだ
い-adjective	Adj + はずだ	高いはずだ
な-adjective	Adjな + はずだ	便利なはずだ
Noun	Nounの + はずだ	先生のはずだ

Formation Diagram

[ Verb (dictionary form) ] + はずだ
[ い-adjective ] + はずだ
[ な-adjective ] + はずだ
[ Noun ] + の + はずだ

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3. Comparative Analysis

• ～に違いない (～にちがいない): Also expresses certainty but is stronger, meaning "must be".
  • Example: 彼は忙しいに違いない。 (He must be busy.)
• ～べきだ: Indicates an obligation or duty, meaning "should".
  • Example: 約束を守るべきだ。 (You should keep your promises.)
• Difference: ～はずだ is based on logical expectation, whereas ～に違いない is a strong conviction, and ～べきだ expresses moral obligation.

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4. Examples in Context

Formal

1. 彼は今日来るはずです。
   • Kare wa kyō kuru hazu desu.
   • He is supposed to come today.
2. この書類はもう届いているはずですが、確認できますか。
   • Kono shorui wa mō todoite iru hazu desu ga, kakunin dekimasu ka.
   • The documents should have arrived already; can you confirm?

Informal

1. あの店は今日休みのはずだよ。
   • Ano mise wa kyō yasumi no hazu da yo.
   • That shop is supposed to be closed today.
2. 彼女は知ってるはずだ。
   • Kanojo wa shitteru hazu da.
   • She should know.

Written

1. 計画は順調に進んでいるはずだ。
   • Keikaku wa junchō ni susunde iru hazu da.
   • The plan should be progressing smoothly.

Spoken

1. もうすぐ電車が来るはずだ。
   • Mō sugu densha ga kuru hazu da.
   • The train should be arriving soon.

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5. Cultural Notes

Cultural Relevance

• In Japanese culture, expressing certainty carefully is important to maintain politeness and avoid misunderstandings.
• Using ～はずだ allows the speaker to state expectations without asserting absolute certainty, which aligns with the indirect communication style often preferred in Japan.

Idiomatic Expressions

• はずがない: Means "cannot be" or "there's no way that...".
  • Example: あの人が犯人のはずがない。
    • Ano hito ga hannin no hazu ga nai.
    • That person can't be the culprit.

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6. Common Mistakes and Tips

Error Analysis

• Using the wrong particle with nouns: Forgetting to add の before はずだ when using nouns.
  • Incorrect: 学生はずだ。
  • Correct: 学生のはずだ。
• Confusing with ～べきだ: Using ～はずだ when expressing an obligation rather than an expectation.
  • Remember: Use ～べきだ for duties or obligations.

Learning Strategies

• Mnemonic Device: Think of はず as "has to (be)" to remember it expresses expectation.
• Practice: Create sentences using personal expectations to internalize the structure.

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7. Summary and Review

Key Takeaways

• ～はずだ expresses expectation based on reasoning.
• Structure changes slightly depending on the predicate (verb, adjective, noun).
• Be cautious with particles and ensure proper formation.

Quick Recap Quiz

1. How do you say "She should arrive tomorrow" using ～はずだ?
   • Answer: 彼女は明日到着するはずだ。
     Kanojo wa ashita tōchaku suru hazu da.
2. True or False: You use の before はずだ when attaching to verbs.
   • Answer: False. の is used with nouns.
3. What is the difference between ～はずだ and ～に違いない?
   • Answer: ～はずだ expresses expectation based on reasoning, while ～に違いない expresses strong conviction or certainty.

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Feel free to revisit the examples and explanations to reinforce your understanding of ～はずだ. Practice by creating your own sentences to describe things you expect to happen!

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