Læreren beder os om at åbne sangbogen og følge noderne nøje.

Because -en is the Danish definite article attached to the noun.

• lærer = teacher / a teacher
• læreren = the teacher

Danish usually puts the at the end of the noun instead of using a separate word like English does.

So:

• Læreren beder os ... = The teacher asks us ...

at bede nogen om at gøre noget is a very common Danish pattern. It means:

• to ask someone to do something

Breakdown:

• beder = asks
• os = us
• om at = introduces what we are being asked to do
• åbne ... og følge ... = the actions

So:

• Læreren beder os om at åbne sangbogen ...
  = The teacher asks us to open the songbook ...

This is one of those expressions that is best learned as a whole pattern:

• Jeg bad ham om at komme. = I asked him to come.
• Hun beder os om at vente. = She asks us to wait.

Because os is the object form of we.

Compare English:

• we ask = subject
• asks us = object

In Danish:

• vi = we
• os = us

So in this sentence:

• Læreren = subject
• beder = verb
• os = object

That is why os is required.

Because at is the infinitive marker, like to in English.

• at åbne = to open
• at følge = to follow

When two infinitives are joined by og (and), Danish often uses at only once if both verbs belong to the same structure.

So:

• om at åbne sangbogen og følge noderne nøje

means:

• to open the songbook and follow the notes carefully

You could think of it as:

• om at [åbne ... og følge ...]

The at applies to both verbs.

Because Danish, like German, often forms compound nouns.

• sang = song
• bog = book
• sangbog = songbook / song book
• sangbogen = the songbook

This is very normal in Danish. English sometimes writes these as one word, two words, or hyphenated, but Danish strongly prefers one compound word.

Other examples:

• skolebog = schoolbook
• arbejdsdag = workday
• musiklærer = music teacher

Danish usually expresses definiteness with an ending on the noun.

• sangbog = songbook

• sangbogen = the songbook

• noder = notes / sheet music
• noderne = the notes

Very roughly:

• singular common gender often takes -en
• plural often takes -ne

So the sentence uses definite forms because it refers to specific things:

• the songbook
• the notes

Here noderne means the musical notes or more naturally the sheet music / the notation.

The singular is:

• en node = a note

The plural is:

• noder = notes
• noderne = the notes

In a musical classroom context, følge noderne means something like:

• follow the notes
• follow the music
• keep your eyes on the notation

So it is not about written notes in a notebook; it is specifically musical notation.

nøje means carefully, closely, or exactly depending on context.

Here:

• følge noderne nøje = follow the notes carefully / closely

It functions as an adverb describing how to follow the notes.

Putting it after the object is normal in Danish:

• følge noderne nøje
• literally: follow the notes carefully

That word order is very natural.

Because Danish is a V2 language in main clauses. That means the finite verb usually comes in the second position.

In this sentence:

• Læreren = first element
• beder = finite verb in second position

So:

• Læreren beder os ...

This is standard Danish sentence structure.

You can see the same thing if another element comes first:

• I dag beder læreren os om at åbne sangbogen.
  = Today, the teacher asks us to open the songbook.

Now I dag is first, so beder still stays second, and læreren moves after it.

In standard Danish, with this meaning, om is normally needed.

The usual pattern is:

• bede nogen om at gøre noget

So:

• Læreren beder os om at åbne sangbogen. = correct

Without om, it sounds wrong or at least nonstandard in this context.

So it is best to learn:

• bede + someone + om at + infinitive

The letter å is a separate Danish vowel. It sounds somewhat like the vowel in English more or awe, though not exactly the same.

• åbne is roughly pronounced like AWB-nuh
• the b is soft in connected speech, so the exact sound may be less sharp than an English b

A few useful points:

• å is not the same as a
• æ, ø, and å are all separate vowels in Danish
• pronunciation in Danish is often less fully pronounced than spelling suggests

If you are learning, the important first step is just to recognize that åbne begins with the å sound, not a plain English a.

Because og simply links two infinitives here:

• åbne sangbogen
• følge noderne nøje

They are part of the same om at ... structure, so no comma is needed:

• ... om at åbne sangbogen og følge noderne nøje.

That works just like English:

• ... to open the songbook and follow the notes carefully.

Often yes, but not always. In this sentence it is very close to English:

• følge noderne = follow the notes / follow the music

More generally, følge can mean:

• follow physically
  
  • Han følger efter mig. = He follows me.
• follow instructions, rules, a line of thought, music, etc.
  
  • Følg instruktionerne. = Follow the instructions.
  • Jeg kan ikke følge dig. = I can't follow you.
    meaning I can't understand your reasoning

So here it means to keep track of the written music as you sing or play.