Garagen er tom endnu, fordi vi stadig mangler nogle hylder.

Because Danish usually marks the by adding an ending to the noun.

• en garage = a garage
• garagen = the garage

So garagen is the definite singular form.

A useful extra point:

• If an adjective comes directly before the noun, Danish normally uses den/det/de instead of the ending alone:
  • den tomme garage = the empty garage

But in your sentence, tom comes after er, so it is not part of the noun phrase. That is why garagen er tom is correct.

Because garage is a common-gender singular noun: en garage.

Predicative adjectives in Danish agree with the noun in gender and number:

• common gender singular: tom
• neuter singular: tomt
• plural: tomme

So:

• Garagen er tom = correct
• Huset er tomt = The house is empty
• Værelserne er tomme = The rooms are empty

Since garage is an en-word, you use tom.

Here endnu means something like still, so far, or as of now.

So Garagen er tom endnu means the garage is empty up to this point in time.

A very common pattern is:

• Han er her endnu = He is still here
• De er ikke kommet endnu = They haven’t arrived yet

That shows an important difference from English:

• in positive sentences, endnu often matches English still
• in negative sentences, endnu often matches English yet

Yes, they can both often be translated as still, but they are not always used in exactly the same way.

In this sentence:

• endnu goes with the state tom and gives the sense still / so far
• stadig goes with mangler and means the situation continues: we still lack

So the sentence is basically saying:

• the garage is still empty
• because we still don’t have some shelves

There is some overlap between endnu and stadig, but the sentence sounds natural as written.

A simple way to remember it:

• stadig often stresses continuation
• endnu often stresses up to now

Mangler is the present tense of at mangle, which means to lack, to be missing, or sometimes to still need.

So:

• vi mangler nogle hylder literally means we lack some shelves
• in more natural English, it may be understood as we still need some shelves or we don’t have the shelves yet

Important: at mangle is not the same as at savne.

• at mangle = to lack / not have
• at savne = to miss someone or something emotionally

So here it is about not having enough shelves yet, not about emotionally missing them.

Because nogle is the usual word for some with plural countable nouns in affirmative statements.

• Vi mangler nogle hylder = We need / are missing some shelves

A beginner-friendly rule is:

• nogle = some
• nogen = any in many questions and negatives

For example:

• Har du nogle bøger? = Do you have some books?
• Har du nogen bøger? = Do you have any books?
• Jeg har ikke nogen bøger = I don’t have any books

In this sentence, the speaker is simply referring to an unspecified number of shelves, so nogle is the natural choice.

The singular is en hylde = a shelf.

Its basic forms are:

• en hylde = a shelf
• hylden = the shelf
• hylder = shelves
• hylderne = the shelves

So hylder is just the normal plural form here.

Because fordi introduces a subordinate clause, and Danish subordinate clauses usually do not use main-clause word order.

Compare:

Main clause

• Vi mangler stadig nogle hylder

Here the finite verb comes early, as usual in Danish main clauses.

Subordinate clause after fordi

• fordi vi stadig mangler nogle hylder

Here the adverb stadig comes before the finite verb mangler.

So the pattern is:

• fordi + subject + adverb + verb

This is one of the most important word-order differences for English speakers learning Danish.

In standard written Danish, you should prefer:

• fordi vi stadig mangler nogle hylder

You may sometimes hear main-clause-like word order after fordi in spoken Danish:

• fordi vi mangler stadig nogle hylder

But as a learner, the safest and most standard choice is the subordinate order with stadig before the verb.

So for normal careful Danish, stick with:

• fordi vi stadig mangler nogle hylder

Yes, absolutely. Garagen er stadig tom is also natural Danish.

The difference is mainly one of nuance:

• Garagen er stadig tom = stresses that the empty state continues
• Garagen er tom endnu = stresses that, up to now, it is still empty

In many situations, both would work. The version with endnu can feel a little more like so far or at this point.

So if you were unsure, stadig would also be a perfectly natural choice here.