Learn Hardcore Japanese: eiga ga owaru made, tosyokan de benkyousimasu. - I will study at the library until the movie ends.

The plain form (終わる) is required in most subordinate clauses like:
- ～まで (until)
- ～とき (when)
- ～前に (before)
The non-past form here doesn’t mean “present”; it means “the point in time when it happens” (which is in the future from now).

Using:

映画が終わりますまで → ungrammatical in standard Japanese.
映画が終わったまで → also wrong for this meaning. Past tense + まで is rare and has a different, limited use.

What exactly does まで mean here? How is it different from までに?

In this sentence, まで marks the end point of a continuous action:

映画が終わるまで、図書館で勉強します。
→ I will study at the library *until the movie is over.*
(You are studying the whole time, from now up to the moment the movie ends.)

Contrast with までに:

映画が終わるまでに、レポートを終えます。
→ I will finish the report *by the time the movie is over.*

Differences:

まで:
- Focuses on a period that continues up to a point.
- Often used with verbs of continuing (勉強する, 待つ, 働く, etc.).
までに:
- Marks a deadline; something just has to be done by that time, not continuously.

So まで = “until (that time)”;
までに = “by (that time)”.

Why is the particle が used after 映画, and not は or を?

Here, 映画が終わる is a small self-contained clause: “the movie ends.”

が marks the subject of the verb 終わる:
- 映画が終わる = the movie ends / the movie finishes

Why not は?

は is a topic marker, not a basic subject marker.
You could say 映画は終わるまで…, but it would sound awkward and unnatural here; 映画 is not the main topic of the whole sentence. The focus is on you studying, with “the movie” just being the thing that ends.

Why not を?

を marks a direct object.
終わる in this pattern is intransitive (“to end (by itself)”).
If you wanted to say “to finish the movie (actively)”, you’d need the transitive verb 終える:
- 映画を終える = to finish (watching/doing) the movie.

So:

映画が終わる → the movie ends (by itself).
映画を終える → [someone] finishes the movie.

Why is 勉強します in “present tense” if the meaning is “I will study”?

Japanese has essentially two tenses:

non-past: ～る / ～ます
past: ～た / ～ました

The non-past tense covers present, habitual, and future. So:

勉強します
- can mean I study, I am going to study, or I will study, depending on context.

In this sentence, the presence of 終わるまで clearly places the action in the future, so natural English becomes:

I will study at the library until the movie is over.

But grammatically, Japanese just uses the same non-past form.

Why do we use で after 図書館 and not に?

で marks the place where an action happens:

図書館で勉強します。
→ I (will) study *at the library.*

Contrast:

に often marks a destination or location of existence:
- 図書館に行きます。= I will go to the library.
- 図書館にいます。 = I am at the library (existence).

So:

図書館で勉強します → the action of studying happens at the library.
If you said 図書館に勉強します, it would be wrong; 勉強する needs で for “at (place of action).”

Can I change the word order? For example: 図書館で映画が終わるまで勉強します。 Is that okay?

Yes, that order is perfectly natural:

映画が終わるまで、図書館で勉強します。
図書館で映画が終わるまで勉強します。

Both mean the same: I will study at the library until the movie is over.

Nuance:

Japanese word order is flexible, but:
- The main verb (勉強します) usually comes at the end.
- The clause modifying “until” (映画が終わる) must come right before まで.
Details like 図書館で can move around as long as the meaning stays clear and natural.

So you can move 図書館で, but you cannot split 映画が終わる away from まで.

How would this sentence change if I used 終わったら instead of 終わるまで?

Compare:

映画が終わるまで、図書館で勉強します。
→ I will study at the library *until the movie is over.*
映画が終わったら、図書館で勉強します。
→ When / after the movie is over, I will study at the library.

Difference:

～まで:
- Describes an action that continues up to a certain point.
- You are already studying, and stop when the movie ends.
～たら:
- Describes something that happens after a condition is met.
- You start studying only after the movie is over.

So:

終わるまで: you are studying before and up to the end of the movie.
終わったら: you are not studying during the movie; you start after it ends.

Can I say this sentence in a casual way? What changes?

Yes. To make it casual, you mainly change the polite ～ます form to the plain form:

Polite:
- 映画が終わるまで、図書館で勉強します。
Casual:
- 映画が終わるまで、図書館で勉強する。

Notes:

The verb before まで (終わる) is already plain, so it doesn’t change.
Only 勉強します → 勉強する changes for casual speech.
You might also drop some words in very casual speech, depending on context:
- 映画終わるまで、図書館で勉強する。 (dropping が)
- But 映画が終わるまで is the safe, clear form.

Why is there no “I” in the Japanese sentence?

Japanese often omits the subject when it is obvious from context:

In English, we must say “I will study…”.
In Japanese, if it is clear you are talking about yourself, わたしは (I) is simply left out:
- (わたしは) 映画が終わるまで、図書館で勉強します。

This is completely natural and very common. You only add わたしは, ぼくは, etc. when:

You need to clarify who is doing the action, or
You want to contrast with someone else (e.g., “I will study at the library, but my friend will watch the movie.”).

What is a more literal, word-by-word breakdown of this sentence?

Sentence: 映画が終わるまで、図書館で勉強します。

Breakdown:

映画 (えいが) = movie, film
が = subject marker
終わる (おわる) = to end, to be over (intransitive)
まで = until (up to the time when…)
、 = comma (just a pause)
図書館 (としょかん) = library
で = at (place where the action happens)
勉強します (べんきょうします) = (I) study / will study (polite form)

Very literal sense:

映画が終わるまで = until the movie ends
図書館で勉強します = (I) will study at the library.

Put together:

Until the movie ends, (I) will study at the library.