Mañana pasaré por la biblioteca antes de ir a la universidad.

Tomorrow I will stop by the library before going to the university.

Breakdown of Mañana pasaré por la biblioteca antes de ir a la universidad.

• yo: I
• ir: to go
• a: to
• antes de: before
• la biblioteca: the library
• mañana: tomorrow
• la universidad: the university
• pasar por: to stop by

Questions & Answers about Mañana pasaré por la biblioteca antes de ir a la universidad.

Why does the sentence start with Mañana?

Mañana means tomorrow, and it sets the time for the whole sentence.

Starting with Mañana is very natural in Spanish, just like Tomorrow, I'll stop by the library... in English. Spanish word order is fairly flexible, so you could also say:

• Pasaré por la biblioteca mañana antes de ir a la universidad.

But putting Mañana first is common when the speaker wants to establish the time right away.

Why is it pasaré? What tense is that?

Pasaré is the first-person singular simple future of pasar.

So:

• pasaré = I will pass / I will stop by

The ending -é tells you it means I will.

This is formed by taking the infinitive pasar and adding future endings:

• pasar + é → pasaré

In this sentence, it refers to a future action happening tomorrow.

Could you also say voy a pasar instead of pasaré?

Yes. Voy a pasar por la biblioteca... is also correct and natural.

Both forms can refer to the future:

• pasaré = simple future
• voy a pasar = near future / going to

In everyday Spanish, especially in speech, ir a + infinitive is very common. The simple future is also common, and here it sounds completely normal.

So both of these work:

• Mañana pasaré por la biblioteca...
• Mañana voy a pasar por la biblioteca...

The difference is usually small in this kind of sentence.

What does pasar por mean here?

Here, pasar por means something like:

• to stop by
• to go by
• to swing by

So pasaré por la biblioteca does not usually mean a full visit with focus on the destination itself. It often suggests going there briefly, or going by it on the way somewhere else.

That fits well with the rest of the sentence:

• antes de ir a la universidad = before going to university

So the idea is: Tomorrow I'll stop by the library before going to university.

Why is it por la biblioteca and not a la biblioteca?

This is an important difference.

• ir a la biblioteca = to go to the library
• pasar por la biblioteca = to pass by / stop by the library

So the preposition changes the meaning:

• a points to a destination
• por suggests movement through/by a place, or a brief stop

If you said:

• Mañana iré a la biblioteca antes de ir a la universidad

that would mean Tomorrow I’ll go to the library before going to university.

But pasaré por la biblioteca suggests more of a quick stop or passing by.

Why isn’t yo included? Shouldn’t it be Yo pasaré?

In Spanish, subject pronouns are often omitted because the verb ending already tells you who the subject is.

Here:

• pasaré clearly means I will

So yo is not necessary.

You could say:

• Yo pasaré por la biblioteca...

but that usually adds emphasis, contrast, or clarity. For example:

• Yo pasaré por la biblioteca, pero tú ve directamente a la universidad.
• I’ll stop by the library, but you go straight to the university.

Without special emphasis, leaving out yo is the most natural choice.

Why is it antes de ir and not just antes ir?

Because in Spanish, when antes is followed by an infinitive, you normally use:

• antes de + infinitive

So:

• antes de ir = before going

This is the standard structure.

Examples:

• antes de comer = before eating
• antes de salir = before leaving
• antes de estudiar = before studying

So in your sentence:

• antes de ir a la universidad = before going to university

Why is it a la universidad? Why is there an article?

Spanish often uses the definite article with places and institutions where English may not.

So:

• a la universidad = literally to the university

Even though English often says to university or to college in some varieties, Spanish normally uses the article here.

Also, a + la does not contract. So:

• a + la = a la

Only these contract in standard Spanish:

• a + el = al
• de + el = del

So:

• a la universidad is correct
• not al universidad

Why is it la biblioteca and not just biblioteca?

Spanish usually uses an article with nouns like this when referring to a known place or institution.

So:

• la biblioteca = the library

Even if English might sometimes say something more generally like I’m going to library in an informal learner-style translation, Spanish normally needs the article:

• Voy a la biblioteca.
• Paso por la biblioteca.

In this sentence, la biblioteca most naturally means the library that is relevant in context, such as the usual one near the speaker, school, or route.

What is the function of de in antes de ir?

Here, de is simply part of the fixed structure antes de.

You should think of it as a chunk:

• antes de = before

Then it can be followed by:

• an infinitive: antes de ir
• a noun: antes de la clase

Examples:

• antes de salir = before leaving
• antes de la reunión = before the meeting

So in this sentence, de is not being translated word-for-word on its own; it belongs to antes de.

What does the accent mark in pasaré do?

The accent mark shows where the stress goes:

• pasaré → stress on the last syllable: pa-sa-RÉ

It also helps distinguish forms. Compare:

• pasare — a different form or an uncommon word depending on context
• pasaré — I will pass / I will stop by

In regular future forms, the written accent is part of the standard ending:

• hablaré
• comeré
• viviré
• pasaré

So the accent is not optional.

Is this sentence natural in Spanish from Spain?

Yes, it sounds natural.

For Spain, this sentence is perfectly normal:

• Mañana pasaré por la biblioteca antes de ir a la universidad.

It sounds like a natural everyday statement meaning the speaker plans to stop by the library before heading to university.

A native speaker might also say slightly different versions depending on context, for example:

• Mañana voy a pasar por la biblioteca antes de ir a la universidad.
• Mañana pasaré por la biblio antes de ir a la uni.

The last version is more informal, with:

• la biblio = informal for biblioteca
• la uni = informal for universidad

But your original sentence is completely standard and natural.