Bamsen ligger i sengen, og barnet lægger sig ved siden af den, før lyset slukkes.

Because Danish usually adds the definite article to the end of the noun.

• bamse = a teddy bear

• bamsen = the teddy bear

• barn = a child

• barnet = the child

• seng = a bed

• sengen = the bed

• lys = a light
• lyset = the light

This is one of the first big differences from English: instead of putting the before the noun, Danish often adds -en or -et to the noun.

Because Danish nouns belong to different grammatical genders.

• en-words usually take -en in the definite singular

  • en bamse → bamsen
  • en seng → sengen

• et-words usually take -et in the definite singular

  • et barn → barnet
  • et lys → lyset

So the ending depends on whether the noun is an en noun or an et noun.

This is a very common question, because English often uses lie for both ideas.

In Danish, there is a clear difference:

• ligge = to be lying / to be in a lying position
• lægge = to lay / to put / to place

In this sentence:

• Bamsen ligger i sengen = the teddy bear is already lying in the bed
• barnet lægger sig = the child puts themself down, meaning lies down

So ligger describes a state, while lægger sig describes a movement into that state.

Sig is a reflexive pronoun. It means the subject is doing the action to themself.

• lægger sig = lays oneself down / lies down

Without sig, lægge usually needs an object:

• Barnet lægger bamsen i sengen = the child puts the teddy bear in the bed

But here the child is not putting something else down. The child is putting themself down, so Danish uses sig.

Because den refers back to bamsen, and bamse is an en-word.

In Danish, third-person pronouns often match the grammatical gender of the noun:

• en bamse → den
• et barn → det

So:

• ved siden af den = beside it, where it refers to the teddy bear

Even though English just says it, Danish has to choose between den and det.

Ved siden af means beside or next to.

It is a fixed expression:

• ved = by / at
• siden = side
• af = of

Together, it functions like English next to:

• ved siden af den = next to it / beside it

This is a very common phrase in Danish, so it is worth learning as a whole unit.

Because Danish normally says i sengen for being in bed.

• i sengen = in bed / in the bed
• på sengen = on the bed

If someone is lying under the covers or is considered to be in bed, Danish usually uses i sengen.
If something is physically on top of the bed, på sengen may be used instead.

So Bamsen ligger i sengen sounds natural for a teddy bear lying in bed.

Because før introduces a subordinate clause.

In Danish main clauses, the verb is usually in second position:

• Lyset slukkes = the light is turned off

But after a conjunction like før, you get subordinate clause structure:

• før lyset slukkes = before the light is turned off

In this clause, the subject lyset comes before the verb slukkes, which is normal for a subordinate clause.

Slukkes is a passive form.

• at slukke = to turn off / extinguish
• slukkes = is turned off

So:

• lyset slukkes = the light is turned off

The -s passive is very common in Danish. It often corresponds to English is/are + past participle.

Compare:

• Jeg slukker lyset = I turn off the light
• Lyset slukkes = the light is turned off

Yes, that is also possible, but it is slightly different in style.

• før lyset slukkes = before the light is turned off

  • more impersonal, passive

• før man slukker lyset = before one turns off the light / before you turn off the light

  • more active, with an unspecified subject

Both are natural Danish. The sentence you were given uses the passive, which keeps the focus on the light rather than on who turns it off.

Usually bamse means teddy bear or stuffed toy, not a real bear.

A real bear is normally bjørn.

So in a sentence like this, bamsen is almost certainly a teddy bear lying in bed with the child.

This follows normal Danish comma rules.

The comma separates the first clause from the next clause:

• Bamsen ligger i sengen
• og barnet lægger sig ved siden af den

In modern Danish, commas are often used between coordinated clauses when each clause has its own verb. So the comma here is completely normal.

Word-for-word, yes, that is close to the structure. But natural English would usually say:

• the child lies down next to it
• the child gets in beside it

This is a good example of why literal translation can help you understand the grammar, even if it does not always sound natural in English.