I og med at bukselinningen er stram, må den justeres.

I og med at is a conjunction meaning something like since, as, seeing that, or given that.

In this sentence, it introduces the reason:

• I og med at bukselinningen er stram ... = Since the waistband is tight ...

It is fairly common, but it can sound a bit more formal or explanatory than plain fordi.

For comparison:

• Fordi bukselinningen er stram, må den justeres.
• I og med at bukselinningen er stram, må den justeres.

Both are correct, but i og med at can feel slightly more like given the fact that.

Because i og med at works as a fixed expression when it introduces a clause.

So:

• i og med at + clause

Examples:

• I og med at det regner, blir vi hjemme.
• I og med at bukselinningen er stram, må den justeres.

You should generally learn it as one unit: i og med at.

Norwegian very often makes compound nouns, where English would often use two words.

Bukselinningen can be broken down like this:

• bukse = trousers / pants
• linning = waistband
• -en = the definite ending for a masculine/common-gender singular noun

So:

• bukselinning = trouser waistband / pants waistband
• bukselinningen = the trouser waistband / the waistband

This is completely normal in Norwegian. English often separates these ideas more than Norwegian does.

In Norwegian, definiteness is usually marked by attaching an ending to the noun.

So instead of:

• the waistband

Norwegian often uses:

• linningen
• bukselinningen

Here:

• en bukselinning = a waistband
• bukselinningen = the waistband

This is one of the biggest differences from English. Norwegian usually puts the idea at the end of the noun.

Because bukselinningen is a common-gender singular noun, and predicate adjectives usually match that pattern.

Compare:

• En bukselinning er stram.
• Bukselinningen er stram.

But with a neuter noun, you would often get -t:

• Et belte er stramt.

So:

• common gender singular: stram
• neuter singular: stramt

That is why stram is correct here.

This is because Norwegian follows the verb-second rule in main clauses.

The sentence begins with a subordinate clause:

• I og med at bukselinningen er stram

After that comes the main clause:

• må den justeres

In a Norwegian main clause, the finite verb normally comes in second position. Since the reason clause comes first, the verb må must come before the subject den.

So the pattern is:

• [fronted element], [verb], [subject] ...

Examples:

• I dag kommer han.
• Når jeg er ferdig, skal jeg dra.
• I og med at bukselinningen er stram, må den justeres.

This is very important in Norwegian word order.

Den refers back to bukselinningen.

Since bukselinningen is a common-gender noun, the pronoun used for it is den.

So:

• bukselinningen = the waistband
• den = it

English also does this:

• The waistband is tight, so it must be adjusted.

Norwegian avoids repeating the noun and uses den instead.

Yes. Justeres is an -s passive form.

Here:

• justere = to adjust
• justeres = is adjusted / be adjusted

So:

• må den justeres = it must be adjusted

This is a very common Norwegian passive pattern.

You can think of it as similar to:

• Døren åpnes. = The door is opened / opens.
• Bilen selges. = The car is being sold / is for sale.
• Den må justeres. = It must be adjusted.

In English, we usually use be + past participle. Norwegian often uses either that kind of passive or the -s passive.

Yes. This version is perfectly correct, but it can sound a bit formal or technical.

More everyday alternatives might be:

• Fordi bukselinningen er stram, må den justeres.
• Bukselinningen er stram, så den må justeres.

These may sound more natural in casual speech.

So the original sentence is good Norwegian, but depending on context, a simpler version might be more common in conversation.

Yes, the comma is normal here because the sentence starts with a subordinate clause:

• I og med at bukselinningen er stram, må den justeres.

The subordinate clause ends before the main clause begins, so a comma is used to separate them.

This is standard Norwegian punctuation with an initial dependent clause.

Yes, in practice it can often be understood either way depending on context.

Literally, må means must. But in natural English translation, must be adjusted and needs to be adjusted can both fit.

So:

• må justeres = must be adjusted
• often naturally translated as = needs to be adjusted

The exact nuance depends on context:

• strict requirement
• practical necessity
• recommendation based on the situation

In this sentence, it sounds like a practical necessity.