Brillestellet passer godt, bortset fra at brillestangen er løs.

Because Danish, like German, very often forms compound nouns as a single word.

So:

• brille = glasses / eyeglass
• stel = frame
• brillestel = eyeglass frame
• brillestellet = the eyeglass frame

English would usually write this as two words, but Danish normally joins them.

In Danish compounds, the first part is often not the same form you would use when the word stands alone in a sentence.

Even though briller is the normal word for glasses, compounds often use brille-:

• brillestel = glasses frame
• brilleæske = glasses case
• brillebutik = optician’s shop / glasses shop

So this is something learners mostly have to get used to: the compound form is brille-.

Because Danish usually puts the definite article at the end of the noun instead of using a separate word.

So:

• et brillestel = a glasses frame
• brillestellet = the glasses frame

And:

• en brillestang = a glasses arm/temple
• brillestangen = the glasses arm/temple

A separate word like det or den is usually used when there is an adjective before the noun:

• det løse brillestel
• den løse brillestang

Here passer godt means fits well.

With clothing, shoes, glasses, and similar things, at passe often means:

• to fit
• to suit

So Brillestellet passer godt means the frame fits well on the person.

Depending on context, at passe can also mean other things, such as:

• to suit: Den farve passer dig godt = That color suits you well
• to match/go with: De passer godt sammen = They go well together
• to look after: Hun passer barnet = She looks after the child

But in this sentence, it is clearly about physical fit.

Because godt is an adverb here.

• god = good (adjective)
• godt = well / in a good way (adverb)

In passer godt, godt describes how the frame fits, so Danish uses the adverb form.

Compare:

• Det er godt = It is good
• Det passer godt = It fits well

So English well often corresponds to Danish godt.

It means something like:

• except that
• apart from the fact that
• other than that

So the sentence structure is:

• Brillestellet passer godt = The frame fits well
• bortset fra at brillestangen er løs = except that the arm is loose

It introduces one exception to an otherwise positive statement.

Because at introduces a clause.

Here, what follows is a full clause:

• brillestangen er løs = the glasses arm is loose

So Danish uses:

• bortset fra at + clause

Compare:

• bortset fra at brillestangen er løs = except that the arm is loose
• bortset fra brillestangen = except for the arm

So if a full subject + verb follows, at is needed.

Because at introduces a subordinate clause, and subordinate clauses normally keep the basic order:

• subject + verb + rest

So:

• brillestangen = subject
• er = verb
• løs = complement

This is different from main clauses in Danish, where the verb often comes second because of the V2 rule.

Compare:

• Main clause: Brillestangen er løs
• Subordinate clause: ... at brillestangen er løs

No inversion happens here.

It means the arm or temple of the glasses — the part that goes over your ear.

Literally, stang often means rod or bar, but in this context brillestang is the side piece of the glasses.

So a natural English translation is usually:

• the glasses arm
• the temple

rather than the literal the glasses rod.

Because brillestangen is a singular common-gender noun.

Adjectives in Danish change depending on gender and number:

• en stang er løs = a bar/arm is loose
• et led er løst = a joint is loose
• stængerne er løse = the bars/arms are loose

Here the noun is:

• en brillestang
• brillestangen

So the correct form is løs.

The comma separates the main statement from the exception/qualification that follows.

So:

• Brillestellet passer godt = main statement
• bortset fra at brillestangen er løs = limiting comment / exception

The comma helps the sentence read clearly and naturally. In practice, this is a very normal place to put a comma in Danish.