~はず

That's a great question! While both はず (hazu) and べき (beki) can translate to 'should' in English, they carry different nuances.

はず (hazu) indicates a strong expectation or probability based on current information or common sense. It's like saying, 'Based on what I know, this is probably true' or 'It's supposed to be this way.' You're expressing a reasonable assumption.

べき (beki), on the other hand, expresses a strong obligation, recommendation, or moral imperative. It's about what ought to be done or what is right to do. Think of it as 'one should do this' or 'it is proper to do this.'

For example:
• 彼は来るはずです。(Kare wa kuru hazu desu.) - 'He should come' (I expect him to come because he said he would, or it's scheduled).
• 彼は来るべきです。(Kare wa kuru beki desu.) - 'He should come' (He ought to come, it's his duty or a good idea for him to come).

Yes, absolutely! You can use はず (hazu) with past tense verbs to express an expectation or assumption about a past event.

For example:
• 彼は来たはずです。(Kare wa kita hazu desu.) - 'He should have come' (I expected him to come, and I assume he did).
• 彼は昨日行ったはずです。(Kare wa kinō itta hazu desu.) - 'He should have gone yesterday' (I assume he went yesterday).

Good question about conjugation! Here’s how to attach はず (hazu) to different word types:

• Verbs: Use the plain (dictionary) form, plain past form, or plain negative form directly before はず.
　Example: 行くはず (iku hazu - supposed to go), 行ったはず (itta hazu - supposed to have gone), 行かないはず (ikanai hazu - not supposed to go).

• い-adjectives: Use the plain form directly before はず.
　Example: 忙しいはず (isogashii hazu - supposed to be busy).

• な-adjectives: Add な (na) between the adjective and はず.
　Example: きれいなはず (kirei na hazu - supposed to be clean/beautiful).

• Nouns: Add の (no) between the noun and はず.
　Example: 学生のはず (gakusei no hazu - supposed to be a student).

Yes, はず (hazu) is perfectly natural and appropriate for both formal and informal contexts. The politeness level depends on the ending you use after はず.

• For formal situations, you'd typically use はずです (hazu desu) or はずでございます (hazu de gozaimasu).
• For informal situations, you might just say はず (hazu) or はずだよ (hazu da yo).

The core meaning of expectation or supposition remains the same, regardless of formality.

That's an important distinction. はず (hazu) expresses a strong expectation or high probability, but it's not 100% certainty. It's based on logical reasoning, information you have, or common sense.

Think of it as 'it logically should be' or 'it's highly probable.' There's always a slight opening for it to be wrong, even if you're quite confident.

If you want to express absolute certainty, you'd use phrases like に違いない (ni chigainai - 'it must be') or simply state it as a fact.

The negative form of はず (hazu) can be expressed in a couple of ways, depending on what you want to negate.

1. Negating the verb/adjective before はず: This means 'it's supposed to NOT be...' or 'it's not expected to...'
　Example: 彼は来ないはずです。(Kare wa konai hazu desu.) - 'He is not supposed to come.'

2. Negating はず itself: This is less common but can be done with はずがない (hazu ga nai) or はずはない (hazu wa nai), which means 'there's no way that...' or 'it couldn't possibly be...' This expresses a stronger denial of possibility.
　Example: そんなはずはない。(Sonna hazu wa nai.) - 'That couldn't possibly be true.' / 'There's no way that's true.'

Yes, a couple of common pitfalls for learners:

1. Confusing it with べき (beki), as we discussed. Remember, はず is expectation/probability, べき is obligation/recommendation.

2. Incorrectly attaching it to nouns or な-adjectives. Don't forget the の (no) for nouns and な (na) for な-adjectives!
　Incorrect: 学生はず (Gakusei hazu) → Correct: 学生のはず (Gakusei no hazu)
　Incorrect: きれいはず (Kirei hazu) → Correct: きれいなはず (Kirei na hazu)

3. Overusing it when simpler expressions would suffice. Sometimes, a simple statement of fact is better if you are certain.

It's more about logical deduction and expectation than a personal opinion or feeling. While your personal judgment can inform your expectation, はず (hazu) implies that there's some objective basis for that expectation, not just a subjective feeling.

If you want to express a personal feeling or opinion, you'd use phrases like と思います (to omoimasu - 'I think') or と感じます (to kanjimasu - 'I feel').

はず (hazu) is about 'how things should be' based on what's known, rather than 'how I feel about things.'

That's a very natural scenario! If your expectation with はず (hazu) turns out to be wrong, you can express surprise or correction.

For example, if you said:
• 彼は来るはずです。(Kare wa kuru hazu desu.) - 'He should come.'

And then he doesn't, you might say:
• あれ？彼は来なかった。(Are? Kare wa konakatta.) - 'Oh? He didn't come.'
• はずだったのに。(Hazu datta noni.) - 'It was supposed to, but...' (implies disappointment or surprise that it didn't happen).

The use of はず (hazu) doesn't prevent you from being wrong; it just expresses your strong prior expectation.

Yes, there are a few! One of the most common is はずがない (hazu ga nai) or はずはない (hazu wa nai), which means 'there's no way that...' or 'it couldn't possibly be...' It expresses a strong denial or impossibility.

Example:
• そんなはずがない！(Sonna hazu ga nai!) - 'That's impossible!' / 'There's no way that's true!'

You might also hear はずだ (hazu da) at the end of a sentence when something clicks, meaning 'Ah, that's why!' or 'No wonder!' when an expectation is confirmed.

Example:
• 疲れているはずだ。(Tsukarete iru hazu da.) - 'No wonder I'm tired!' (when you realize you stayed up late, for instance).