Vi måste källsortera glaset och plasten innan soprummet stänger.

Källsortera literally means source-sort. It means separating waste into the correct categories where you throw it away, such as glass, plastic, paper, and food waste.

It is a bit more specific than återvinna (to recycle).

• You källsorterar when you sort the waste.
• The material is then återvunnet when it is actually recycled.

Because måste is a modal verb. In Swedish, modal verbs are followed by the infinitive without att.

So you say:

• måste källsortera
• kan komma
• vill äta
• ska gå

This works much like English:

• must sort
• not must to sort

No. In modern Swedish, verbs do not change for person or number.

So you say:

• jag måste
• du måste
• hon måste
• vi måste

The form måste stays the same.

In Swedish, material or category words are often put in the definite singular when talking about them as a category in a practical context, especially with sorting or disposal.

So:

• glaset = the glass / glass waste
• plasten = the plastic / plastic waste

In English, we often just use bare nouns: glass and plastic. Swedish often prefers the definite form here.

Because here they are material nouns, not countable objects.

The sentence is about sorting the material categories glass and plastic, not about multiple individual items called glasses or plastics.

If you wanted to talk about specific objects, you would often use other nouns, for example:

• glasflaskor = glass bottles
• plastförpackningar = plastic packaging

Soprummet comes from the compound noun soprum:

• sop- = garbage/trash
• rum = room

Swedish very often writes compounds as one word, even when English uses two words.

So:

• ett soprum = a garbage room / trash room
• soprummet = the garbage room / trash room

Because innan is used before a clause.

Here, innan is followed by:

• soprummet stänger

That is a full clause, so innan is the natural choice.

Compare:

• innan soprummet stänger = before the garbage room closes
• före stängning = before closing
• före klockan åtta = before eight o’clock

So före is more natural before a noun phrase or time expression, while innan is natural before a full clause.

Swedish often uses the present tense for future meaning when the future event is understood from context or is scheduled/expected.

That is very common after time words such as:

• innan
• när
• om

So innan soprummet stänger means before the garbage room closes, even though the closing happens later.

Because innan introduces a subordinate clause. In Swedish subordinate clauses, the normal order is subject + verb.

So:

• soprummet = subject
• stänger = verb

This gives:

• innan soprummet stänger

A useful comparison:

• Main clause: Soprummet stänger klockan åtta.
• Subordinate clause: Vi måste gå innan soprummet stänger.

Yes. In Swedish, a place or facility can be the subject of stänga.

So soprummet stänger means that the room becomes closed, locked, or unavailable.

You could also say:

• de stänger soprummet = they close the garbage room

But the version in the sentence is completely natural and common.