N4-G-056
な-adjective + な はずです (Should be / Expected to be [Na-adj])
Core / Reasonable Expectation & Logical Certainty
👀 Layer A: Visual Guide
📝 Quick Summary
This grammar pattern connects a な-adjective to はずです by attaching な (na) to express a strong, logical expectation regarding a state or condition based on evidence, reputation, or facts.
Structure: [な-adjective Base] + な + はずです
Example 1: この へやは もりの なかに ありますから、しずかな はずです (Because this room is inside the forest, it should be quiet).
Example 2: あたらしい スマホは べんりな はずです (The new smartphone should be convenient).
🔍 Layer B: Deepening
💡 Raya’s Hack
The NA Bridge Before HAZU DESU
Because hazu (はず) acts grammatically as a noun, な-adjectives modify it using standard noun-modifying rules:
– Present Affirmative: 静か な はずです (shizuka na hazu desu – should be quiet)
– Present Negative: 静か じゃない はずです (shizuka janai hazu desu – should not be quiet)
– Past Affirmative: 静か だった はずです (shizuka datta hazu desu – should have been quiet)
Never keep だ (da) before hazu in present affirmative!
🚧 Joy’s Mistake
Scene: Joy is explaining that a new gadget should be convenient.
Joy: 「この ツールは べんりだ はずです。」
(Kono tsuuru wa benri da hazu desu.)
❌ Used “da” before はず!
Why?
Joy attached the plain copula da directly before hazu desu. For な-adjectives in present affirmative tense before hazu, you MUST replace da with na.
Correct: 「この ツールは べんりな はずです。」 (This tool should be convenient.)
🔥 Layer C: Retrieval Practice Loop
Retrieve and apply! Express logical expectations with な-adjectives. (Hiragana and English only)
Level 1: Structure Building (Na-adj + な はずです)
Q1. Should be quiet (しずか[な])
Q2. Should be convenient (べんり[な])
Q3. Should be free / have time (ひま[な])
Q4. Should be simple / easy (かんたん[な])
Q5. Should not be necessary (ひつようじゃない)
Level 2: Full Sentences
Q6. Because it is inside the forest, this room should be quiet. (もりの なかですから / しずか[な])
Q7. Because today is a holiday, he should be free. (きょうは やすみだから / ひま[な])
Q8. This new computer should be convenient. (この あたらしい パソコンは / べんり[な])
Q9. The test procedure should be simple. (てすとが / かんたん[な])
Q10. Because he exercised every day, he should be healthy/energetic. (まいにち うんどうしましたから / げんき[な])
