Hvis dugen bliver plettet igen, tager jeg den anden dug fra skabet.

Because Danish marks definiteness in two different ways here.

• dugen = the tablecloth

  • dug = tablecloth
  • -en makes it definite: dugen

• den anden dug = the other tablecloth

  • When a noun has a word like den, anden, samme, or an adjective phrase in front of it, Danish normally uses the indefinite noun form.
  • So you say den anden dug, not den anden dugen.

A useful comparison:

• dugen = the tablecloth
• den nye dug = the new tablecloth
• den anden dug = the other tablecloth

So the noun changes form because the definiteness is being expressed differently.

Here, den anden dug most naturally means the other tablecloth.

In Danish, anden can sometimes mean:

• other
• second

In this sentence, the context suggests there is one tablecloth currently in use, and there is another one in the cupboard. So the other tablecloth is the most natural reading.

If the context were about an ordered list, anden could mean second, but that is less likely here.

Because bliver plettet focuses on the action or change: gets stained.

• bliver plettet = gets stained / becomes stained
• er plettet = is stained

So:

• Hvis dugen bliver plettet igen ... = If the tablecloth gets stained again ...
• Hvis dugen er plettet ... = If the tablecloth is stained ...

The first one describes something happening. The second one describes a state.

This is a very common Danish pattern:

• blive + past participle = a passive meaning like get ...ed
• være + past participle/adjective = a state meaning like be ...ed

In this sentence, plettet is the past participle used in a passive construction with bliver.

It comes from the idea of staining/spotting something, and it means stained or spotted.

So:

• plet = stain / spot
• plettet = stained / spotted

In practice, learners often experience plettet as almost adjective-like, because it describes the condition of the tablecloth. But grammatically in bliver plettet, it is part of a passive structure.

Because Danish main clauses follow the verb-second rule.

The first part, Hvis dugen bliver plettet igen, is a subordinate clause. When that whole clause comes first, the main clause must still put the finite verb in second position:

• Hvis dugen bliver plettet igen, tager jeg den anden dug ...

Structure:

1. fronted element: Hvis dugen bliver plettet igen
2. finite verb: tager
3. subject: jeg

If you put the main clause first, the order becomes normal again:

• Jeg tager den anden dug fra skabet, hvis dugen bliver plettet igen.

So tager jeg is not random; it is standard Danish word order.

Because Danish often uses the present tense for future meaning when the context already makes the time clear.

So:

• Hvis dugen bliver plettet igen, tager jeg den anden dug fra skabet.

means something like:

• If the tablecloth gets stained again, I’ll take the other tablecloth from the cupboard.

Danish does this very often, especially in:

• conditionals
• plans
• schedules
• predictable future situations

You do not need a special future form like English will in every case.

igen means again.

Here it belongs with bliver plettet:

• bliver plettet igen = gets stained again

This placement is natural because igen modifies the whole event of becoming stained.

So the idea is not just that the cloth is stained, but that this happens another time.

Both are possible, but they are slightly different in feel.

• fra skabet = from the cupboard

  • neutral
  • focuses on the source

• ud af skabet = out of the cupboard

  • more physical
  • emphasizes movement out of it

So:

• tager jeg den anden dug fra skabet = I take the other tablecloth from the cupboard
• tager jeg den anden dug ud af skabet = I take the other tablecloth out of the cupboard

The version with fra is perfectly natural and slightly less vivid.

Because the sentence begins with a subordinate if-clause:

• Hvis dugen bliver plettet igen, ...

In Danish, it is standard to separate that clause from the main clause with a comma:

• Hvis dugen bliver plettet igen, tager jeg den anden dug fra skabet.

So the comma marks the boundary between:

• the condition
• the result

This is very common with hvis, når, fordi, selvom, and similar conjunctions.