Die Wohnung ist zu laut, darum lese ich heute in der Bibliothek.

Because Wohnung is a feminine noun in German. German nouns have grammatical gender, and Wohnung takes feminine articles:

• die Wohnung = the apartment
• eine Wohnung = an apartment

This gender is grammatical, not logical, so it simply has to be learned with the noun.

Zu laut means too loud.

This is different from sehr laut, which means very loud.

• sehr laut = very loud
• zu laut = too loud, louder than is acceptable or comfortable

So Die Wohnung ist zu laut means the apartment is not just loud, but uncomfortably or excessively loud.

Because the sentence is really made of two main clauses:

• Die Wohnung ist zu laut
• darum lese ich heute in der Bibliothek

In German, two main clauses are often separated by a comma, especially when linked by words like darum, deshalb, or deswegen.

So the comma helps mark the break between:

• the reason/problem
• the consequence/result

Darum means therefore, that’s why, or for that reason.

It introduces a result, not a subordinate clause.

Compare:

• Die Wohnung ist zu laut, darum lese ich heute in der Bibliothek.
  = The apartment is too loud, therefore I’m reading in the library today.

• Ich lese heute in der Bibliothek, weil die Wohnung zu laut ist.
  = I’m reading in the library today because the apartment is too loud.

So:

• darum = therefore / that’s why / as a result
• weil = because

They express a similar relationship, but the sentence structure is different.

Because German main clauses follow the verb-second rule.

That means the conjugated verb must come in the second position. If darum comes first, then the verb must come next:

• Darum lese ich ...

Not:

• Darum ich lese ... ❌

You can think of it like this:

1. darum = position 1
2. lese = position 2
3. ich comes after the verb

This happens with many sentence starters:

• Heute lese ich ...
• Darum lese ich ...
• In der Bibliothek lese ich ...

Because the subject is ich, and the verb has to be conjugated.

The infinitive is lesen = to read

Present tense conjugation:

• ich lese
• du liest
• er/sie/es liest
• wir lesen
• ihr lest
• sie/Sie lesen

So ich lese means I read or I am reading, depending on context.

Heute means today, and in German adverbs of time are often placed fairly early in the sentence.

In darum lese ich heute in der Bibliothek, the word order is very natural:

• darum = first position
• lese = verb in second position
• ich = subject
• heute = time expression
• in der Bibliothek = place

German often prefers something like:

• time before place

So heute in der Bibliothek sounds very normal.

Yes, German word order is flexible, though some versions sound more natural than others.

For example:

• Darum lese ich heute in der Bibliothek.
  very natural

• Darum lese ich in der Bibliothek heute.
  possible, but less natural in most contexts

• Heute lese ich darum in der Bibliothek.
  possible only in a special context, but not the most natural way to say this

The original sentence is a very standard, idiomatic word order.

Because in can take either the dative or the accusative, depending on meaning.

Here, the meaning is location: the speaker is reading in the library, not moving into it. So German uses the dative:

• in der Bibliothek = in the library

If there were movement toward the library, you would use the accusative:

• Ich gehe in die Bibliothek. = I’m going into the library.

So:

• where? → dative
• where to? → accusative

It is feminine. The noun’s gender has not changed; the article changes because of case.

For the feminine noun die Bibliothek:

• nominative: die Bibliothek
• accusative: die Bibliothek
• dative: der Bibliothek
• genitive: der Bibliothek

Since in here requires the dative for location, die becomes der:

• in der Bibliothek

Not here.

German does have contractions such as:

• in dem → im
• an dem → am
• zu dem → zum
• zu der → zur

But in der does not contract into a standard form.

So you must say:

• in der Bibliothek

not a shortened version.

Usually, yes. Wohnung commonly means apartment or flat.

A native English speaker should note:

• in American English, apartment
• in British English, often flat

So depending on the variety of English, the translation may differ slightly, but the German word is the same.

Yes, it sounds completely natural.

It expresses:

1. a problem: Die Wohnung ist zu laut
2. a consequence: darum lese ich heute in der Bibliothek

A German speaker could also say similar things like:

• Die Wohnung ist zu laut, deshalb lese ich heute in der Bibliothek.
• Weil die Wohnung zu laut ist, lese ich heute in der Bibliothek.

But the original sentence is perfectly normal and idiomatic.

In many everyday situations, they all mean roughly therefore / that’s why / for that reason.

So these are all possible:

• Die Wohnung ist zu laut, darum lese ich heute in der Bibliothek.
• Die Wohnung ist zu laut, deshalb lese ich heute in der Bibliothek.
• Die Wohnung ist zu laut, deswegen lese ich heute in der Bibliothek.

For most learners, the important point is that all three usually trigger verb-second word order in the following clause:

• darum lese ich
• deshalb lese ich
• deswegen lese ich

The differences are mostly about style and personal preference, not basic grammar.

It can mean either, depending on context.

German simple present often covers both meanings:

• ich lese = I read / I am reading

In this sentence, because of heute, it most naturally means something like:

• I’m reading in the library today or
• I will read in the library today

German often relies on context rather than using a separate progressive form like English am reading.