Learn Hardcore Japanese: asita no siken ni goukakusuru zo.

You might see things like 明日試験 in notes, schedules, or very casual speech; that’s more like a clipped “(I have) exam tomorrow.”
But the fully normal way to say “tomorrow’s exam” as one noun phrase is 明日の試験.

Why is に used after 試験 in 試験に合格する instead of を?

In Japanese, 合格する (“to pass,” “to qualify”) is normally used with に, because the exam is treated as a target or standard, not as a direct object.

試験に合格する = “to pass an exam” / “to succeed in an exam”

Compare:

大学に入る = to enter a university
会社に受かる = to get into a company (be accepted)

So the pattern is:
X に合格する = to pass X

Using 試験を合格する is generally unnatural in modern standard Japanese. You may see it occasionally, but 試験に合格する is the form you should learn and use.

There’s no word for “I” in the Japanese sentence. How do we know it means “I’ll pass the exam”?

Japanese often drops the subject when it’s clear from context. Here, several hints point to “I”:

The topic is “tomorrow’s exam,” something the speaker is going to take.
The ending ぞ expresses the speaker’s strong determination or assertion.
In real conversation, context (who’s talking about whose exam) makes this clear.

So the full, “spelled out” version could be:

（私は）明日の試験に合格するぞ。
“(As for me,) I’ll pass tomorrow’s exam!”

But the 私は is usually dropped as unnecessary.

Why is 合格する in the “dictionary form” (non-past) when it clearly refers to the future (“tomorrow”)?

Japanese does not have a separate future tense. The non-past form (dictionary form) covers both:

present / general facts
future events / intentions

Whether it’s present or future is usually shown by context or time words like 明日 (tomorrow), 来週 (next week), etc.

So:

明日の試験に合格する。
→ The verb is non-past, but 明日 tells us it’s about the future: “(I) will pass…”

The same non-past form can also express determination or a plan, especially with a strong ending like ぞ.

What nuance does ぞ add to the sentence 合格するぞ?

ぞ is a sentence-ending particle that adds:

strong assertion / emphasis
a rough, confident, or sometimes masculine tone
a sense of determination or “Fired up!” feeling

明日の試験に合格するぞ。 can feel like:

“I’m gonna pass tomorrow’s exam!”
“I WILL pass that exam!” (with determination or bravado)

Compared to some other endings:

合格するよ。 – assertive but more neutral / friendly
合格するね。 – sharing feeling, seeking agreement (“I’ll pass, don’t you think?”)
合格するぞ。 – more “pumped up,” rough, or manly-sounding

Is ぞ only used by men? Can women say 合格するぞ?

In standard modern Japanese:

ぞ is strongly associated with male, rough, or informal speech.
It sounds like something you’d expect from a guy hyping himself up, anime characters, close male friends, etc.

Can women use it?

Yes, some women might use ぞ:
- in certain dialects
- to sound deliberately tough, boyish, or comical
- in fiction, to give a “strong” or “rough” character feel
But for a learner, if you identify as female and want normal-sounding, everyday speech, it’s safer to avoid ぞ until you really understand its nuance.

More neutral alternatives for the same basic meaning:

明日の試験に合格するよ。 (still casual, less rough)
明日の試験に合格するから。 (assertive explanation)
明日の試験に合格します。 (polite, no roughness)

Is 明日の試験に合格するぞ polite? Can I say this to my teacher?

No, this sentence is not polite. It’s:

plain form (合格する, not 合格します)
with the rough, emphatic ending ぞ

Saying ～ぞ to a teacher or in a formal situation would usually sound too rough or even rude.

More appropriate polite versions might be:

明日の試験に合格します。
“I will pass tomorrow’s exam.” (neutral, polite)
明日の試験に合格したいです。
“I want to pass tomorrow’s exam.”
明日の試験に合格できるように頑張ります。
“I’ll do my best so that I can pass tomorrow’s exam.”

You’d reserve ～ぞ (and this exact sentence) for friends, self-talk, manga/anime-style speech, etc.

Could I say 明日の試験に合格します instead of 合格するぞ? What changes?

Yes, you can. The difference is mainly politeness and emotional tone:

明日の試験に合格するぞ。
- plain form
- rough, determined, emotionally charged
- feels like hyping yourself up
明日の試験に合格します。
- polite form
- neutral, matter-of-fact statement
- appropriate in formal situations or when talking to people you should respect

The core meaning (“I will pass tomorrow’s exam”) is the same; what changes is how you say it and to whom it’s appropriate.

Could I say 明日の試験を合格する instead of 試験に合格する?

You should avoid 試験を合格する. It’s not the standard pattern.

合格する is (functionally) intransitive: the thing you pass takes に, not を.

Correct pattern:

試験に合格する – to pass an exam
テストに合格する – to pass a test
面接に合格する – to pass an interview

So stick with X に合格する.

What’s the difference between 合格する and 合格できる in this kind of sentence?

合格する = “to pass (an exam)” – just states the passing itself.
合格できる = “to be able to pass / can pass” – focuses on ability or possibility.

Compare:

明日の試験に合格するぞ。
“I WILL pass tomorrow’s exam!” (strong determination)
明日の試験に合格できると思う。
“I think I can pass tomorrow’s exam.” (talking about likelihood/ability)
明日の試験に絶対合格するぞ。
“I’m definitely going to pass tomorrow’s exam!” (very strong determination)

So 合格するぞ is more like a promise/declaration to yourself or others, not a discussion of ability.

How would I say “I hope I’ll pass tomorrow’s exam” instead of the strong “I will pass!” feeling of 合格するぞ?

To express hope rather than firm determination, you can use patterns like:

明日の試験に合格するといいな。
“I hope I’ll pass tomorrow’s exam.”
明日の試験に合格できるといいな。
“I hope I’ll be able to pass tomorrow’s exam.”
明日の試験に合格できればいいな。
“It would be nice if I could pass tomorrow’s exam.”

These sound less like “I WILL definitely do it!” and more like “I really hope this will happen.”