Bokhyllan är dammig, så jag torkar den innan gästerna kommer.

Bokhyllan is the definite singular form of bokhylla (bookshelf).

• en bokhylla = a bookshelf
• bokhyllan = the bookshelf

In Swedish, the definite article is usually attached to the end of the noun as a suffix:

• en bil → bilen
• en stol → stolen
• en bokhylla → bokhyllan

So Bokhyllan är dammig means The bookshelf is dusty.

Because bokhylla is an en-word (common gender noun).

For singular definite nouns:

• en-word → usually adds -en or -n
• ett-word → usually adds -et or -t

Examples:

• en bokhylla → bokhyllan
• en katt → katten
• ett bord → bordet

Since bokhylla already ends in -a, the definite ending appears as -n: bokhylla + n = bokhyllan.

Dammig is an adjective meaning dusty.

It is in the form used with:

• an en-word singular noun
• an indefinite noun phrase, or
• after a verb like är when describing something

Here it describes bokhyllan, which is an en-word, so dammig is the correct form.

Compare:

• en dammig bokhylla = a dusty bookshelf
• bokhyllan är dammig = the bookshelf is dusty
• ett dammigt bord = a dusty table
• de är dammiga = they are dusty

So the ending changes depending on gender and number.

Because den refers back to bokhyllan, and bokhylla is an en-word.

In Swedish:

• den = it / that / the one for en-words
• det = it / that / the one for ett-words

So:

• bokhyllan → den
• bordet → det

Examples:

• Bokhyllan är fin. Jag gillar den.
• Bordet är stort. Jag flyttar det.

Since the object being wiped is the bookshelf, den is correct.

Swedish often uses the present tense to talk about a future action when the time is clear from the context.

Here, innan gästerna kommer (before the guests come) makes it clear that the wiping will happen before a future event. So jag torkar den naturally means something like:

• I wipe it
• I’m wiping it
• I’ll wipe it

depending on context.

This is very common in Swedish. For example:

• Jag ringer dig imorgon. = I’ll call you tomorrow.
• Vi ses på fredag. = We’ll see each other on Friday.

Yes. In this sentence, så means so, in the sense of therefore or as a result.

The structure is:

• Bokhyllan är dammig = cause
• så jag torkar den = result

So it links the two parts:

The bookshelf is dusty, so I wipe it / I’ll wipe it.

Swedish så is extremely common and can have several uses, but in this sentence it is simply a conjunction meaning so.

Because innan means before and introduces a subordinate clause.

The clause gästerna kommer has normal subordinate-clause word order here:

• gästerna = subject
• kommer = verb

So:

• innan gästerna kommer = before the guests come

This is straightforward because there is no extra adverb like inte in the clause. If there were one, Swedish subordinate clauses usually place it before the verb:

• innan gästerna inte kommer would be ungrammatical in this meaning
• compare with a normal subordinate pattern like innan gästerna inte hinner fram where inte comes before hinner

In your sentence, though, it is simply subject + verb.

Gästerna is the definite plural form of gäst (guest).

• en gäst = a guest
• gäster = guests
• gästerna = the guests

So the sentence means before the guests come, not just before guests come in a more general sense.

Swedish definite plural is often formed with a plural ending plus a definite ending:

• gäst → gäster → gästerna
• bil → bilar → bilarna

Because Swedish works like English here: you use the verb är (is/are/am) as the linking verb between the subject and the adjective.

• Bokhyllan = the bookshelf
• är = is
• dammig = dusty

So Bokhyllan är dammig literally matches English very closely:

The bookshelf is dusty.

There is no extra word needed.

Yes. Just like torkar, kommer is a present-tense form, but it can refer to a future event when the context makes that clear.

So innan gästerna kommer means:

• before the guests come
• before the guests arrive

and it refers to a future arrival.

This is one of the most important things for English speakers to get used to: Swedish often uses the present tense where English might prefer will.

In this context, it can often be understood as either come or arrive in English.

• gästerna kommer literally = the guests come
• natural English translation in context = the guests arrive

Swedish komma is very common and often covers both ideas depending on context. When talking about people coming to your home, English often prefers arrive, but Swedish naturally uses komma.

Because the definiteness is already built into the noun ending -na.

• gäster = guests
• gästerna = the guests

Swedish usually does not put a separate word like the before a noun the way English does. Instead, the noun itself changes form.

So:

• the guest = gästen
• the guests = gästerna

That is why there is no separate article.

The sentence has two main parts plus a time clause:

1. Bokhyllan är dammig
   Subject + verb + adjective

2. så jag torkar den
   Conjunction + subject + verb + object

3. innan gästerna kommer
   Subordinate time clause

So the overall structure is:

[Statement] + så + [result/action] + innan + [time clause]

A rough grammar breakdown:

• Bokhyllan = subject
• är = verb
• dammig = subject complement
• så = conjunction
• jag = subject
• torkar = verb
• den = object pronoun
• innan = subordinating conjunction
• gästerna = subject
• kommer = verb

Yes, absolutely.

Both are correct:

• Jag torkar den = I wipe it
• Jag torkar bokhyllan = I wipe the bookshelf

Using den avoids repeating the noun and sounds natural, just like English often uses it instead of repeating the bookshelf.

So the sentence could also be:

Bokhyllan är dammig, så jag torkar bokhyllan innan gästerna kommer.

But that sounds more repetitive than the version with den.

A fairly literal version would be:

The bookshelf is dusty, so I wipe it before the guests come.

A more natural English translation might be:

The bookshelf is dusty, so I’ll wipe it before the guests arrive.

This difference is useful for learners because the Swedish uses present tense forms where English often prefers a future expression.