Estos días, la obra del baño hace tanto ruido que prefiero estudiar en la biblioteca.

Here Estos días means these days, lately, or at the moment. It does not usually refer to a precise set of days on a calendar. It introduces a temporary current situation.

So in this sentence, it suggests: for now / recently, this is what has been happening.

Because Estos días is a time expression placed at the beginning of the sentence. In Spanish, that kind of opening phrase is often separated with a comma in writing.

• Estos días, la obra del baño... = very natural
• Estos días la obra del baño... = also understandable, but the comma helps the rhythm

So the comma is mainly about style and clarity, not a major grammar rule.

In Spain, la obra often means building work, renovation work, or construction work. So la obra del baño means the work being done on the bathroom or the bathroom renovation.

That is a very common use of obra in everyday Spanish in Spain.

It does not mean a literary or artistic work here. The context makes it clear that it means renovation/construction.

Yes, both obra and obras can be used, but they give slightly different ways of viewing the situation.

• la obra = the project as a single piece of work
• las obras = the works / renovations, often emphasizing the activity or multiple tasks involved

So la obra del baño treats the bathroom renovation as one project.
In Spain, you will also hear things like:

• Estamos de obras = We’re having renovation work done
• Las obras hacen mucho ruido = The works make a lot of noise

Because de + el contracts to del in Spanish.

So:

• de + el baño → del baño

This contraction is normally mandatory.

The only common exception is when el is part of a proper name, such as El Escorial:

• de El Escorial (not del Escorial, when it is the actual name)

Here, del baño means something like of the bathroom or, more naturally in English, the bathroom’s / on the bathroom.

Because hacer ruido is the standard expression for to make noise.

• hacer = to do / to make
• ruido = noise

So:

• La obra hace ruido = The work makes noise
• Hace mucho ruido = It makes a lot of noise

This is just the normal collocation in Spanish, so it is best learned as a set phrase: hacer ruido.

Because ruido is a noun, and before nouns Spanish uses tanto/tanta/tantos/tantas, not tan.

• tan

  • adjective/adverb
  • tan ruidosa = so noisy
  • tan lejos = so far

• tanto/a/os/as

  • noun
  • tanto ruido = so much noise
  • tanta gente = so many people

Since ruido is a masculine singular noun, the correct form is tanto.

Tanto ... que means so much ... that or so ... that. It shows a cause-and-result relationship.

In this sentence:

• hace tanto ruido = it makes so much noise
• que prefiero estudiar en la biblioteca = that I prefer to study in the library

So the pattern is:

• [a lot / so much] + que + result

A few similar examples:

• Tengo tanto sueño que me voy a dormir.
  = I’m so sleepy that I’m going to sleep.

• Habla tan rápido que no lo entiendo.
  = He speaks so fast that I don’t understand him.

Notice that with adjectives/adverbs you use tan, but with nouns you use tanto.

Because after preferir, Spanish normally uses an infinitive when the subject stays the same.

• Prefiero estudiar = I prefer to study

The person who prefers and the person who studies are both I, so Spanish uses the infinitive directly.

You do not need a word like to before the infinitive in Spanish.

Compare:

• Prefiero estudiar en la biblioteca.
  = I prefer to study in the library.

But if the subject changes:

• Prefiero que estudies en la biblioteca.
  = I prefer that you study in the library.

Yes. It comes from preferir, which is a stem-changing verb.

The e in the stem changes to ie in stressed forms:

• yo prefiero
• tú prefieres
• él/ella prefiere

But not in nosotros or vosotros:

• nosotros preferimos
• vosotros preferís (Spain)

So prefiero is not random; it follows a very common Spanish pattern.

Because Spanish often uses the definite article with places and institutions where English may or may not use one.

So en la biblioteca is the normal way to say in the library or at the library.

English sometimes drops articles in similar cases, but Spanish usually keeps them:

• en la biblioteca
• en la escuela
• en el hospital

Here, la biblioteca could mean a specific library the speaker has in mind, or simply the library as the place they go to study.

Because Spanish uses the simple present very often for things that are currently happening, especially when they are repeated, ongoing, or generally true for the current period.

So:

• la obra del baño hace tanto ruido
• prefiero estudiar en la biblioteca

sounds natural for a present situation that is affecting the speaker these days.

Spanish could use a progressive form in some contexts, but here it would sound less natural because the sentence is about a continuing situation, not just a single action happening right this second.

So the simple present is exactly what you would expect here.