Hun synes også, at det er uheldigt, når toget kører uden hende.

Synes is the present tense of the verb at synes, which means to think, to feel, or to find in the sense of giving an opinion.

So:

• hun synes = she thinks / she feels / she finds
• There is no extra er here.

In this sentence, synes expresses her opinion about the situation.

This is a very common question.

• synes = to think / feel / find, especially for an opinion or personal judgment
• tror = to believe / think, especially when you are less certain or talking about what you believe to be true

So here:

• Hun synes også, at det er uheldigt = She also thinks/feels that it is unfortunate
• Using tror would sound more like she believes it is unfortunate as a fact, rather than giving her personal reaction.

In many cases, Danish uses synes where English uses think for opinions.

In Danish main clauses, the finite verb usually comes in second position. This is the V2 word order rule.

So the structure is:

• Hun = subject
• synes = finite verb
• også = adverb

That gives:

• Hun synes også ...

This is the natural word order in Danish. English also often says She also thinks, so it may feel familiar here.

At here means that and introduces a subordinate clause.

So:

• Hun synes også, at det er uheldigt
  = She also thinks that it is unfortunate

In English, that is often optional. In Danish, at is very common in this kind of sentence.

Here, det works like it in English in sentences such as:

• It is unfortunate
• It is strange
• It is nice

The real situation being talked about is explained afterward:

• når toget kører uden hende = when the train leaves/goes without her

So Danish uses det as a kind of placeholder:

• det er uheldigt = it is unfortunate

This is very natural in Danish.

Because the adjective is agreeing with det.

The basic form is:

• uheldig = unfortunate

But when an adjective describes a neuter singular noun or pronoun like det, it usually takes -t:

• en uheldig situation
• et uheldigt problem
• det er uheldigt

So in this sentence, uheldigt is the correct form because it goes with det.

These words can all relate to time or condition, but they are used differently.

• når = when, often for something repeated, general, or expected
• da = when, but usually about a specific event in the past
• hvis = if

In this sentence:

• når toget kører uden hende

This suggests a situation like when the train goes without her or whenever the train leaves without her, not one single past event.

So når is the natural choice.

Because after a subordinating conjunction like når, Danish uses normal subordinate clause word order:

• når toget kører

That is:

• når = when
• toget = subject
• kører = verb

In main clauses, Danish often uses verb-second word order. But subordinate clauses usually do not.

Compare:

• Main clause: Toget kører nu.
• Subordinate clause: ..., når toget kører nu.

So når toget kører is correct.

Because toget is the definite form: the train.

• tog = a train
• toget = the train

Danish often adds the definite article to the end of the noun instead of using a separate word like the.

So:

• en bil = a car
• bilen = the car
• et tog = a train
• toget = the train

In Danish, at køre is commonly used for vehicles and transport, including trains, buses, and cars.

So:

• Toget kører can mean the train is running, the train goes, or the train leaves, depending on context.

This is broader than English drive. A train can køre even though nobody is literally driving it in the English sense.

Because uden is a preposition, and after a preposition Danish uses the object form of the pronoun.

So:

• hun = she
• hende = her

After uden (without), you need hende:

• uden hende = without her

Just like in English, you say without her, not without she.

It can suggest both, depending on context.

Literally:

• uden hende = without her

In this sentence, the most natural meaning is that the train goes/leaves and she is not on it. In real context, it may also imply:

• the train left without waiting for her
• the train departed while she was not aboard

So the phrase is simple, but the exact nuance comes from the situation.

The commas mark off subordinate clauses.

You have:

• Hun synes også, at det er uheldigt, når toget kører uden hende.

The clause introduced by at is subordinate, and the clause introduced by når is also subordinate.

So the commas help show the structure:

1. main clause: Hun synes også
2. at-clause: at det er uheldigt
3. når-clause: når toget kører uden hende

In Danish writing, commas are often used to make clause boundaries clear.

In informal writing, you may sometimes see fewer commas, but in standard written Danish, many writers include the comma before a subordinate clause introduced by at.

So in careful written Danish, the version with the comma is a good model:

• Hun synes også, at det er uheldigt, når toget kører uden hende.

For a learner, it is safest to follow the version with commas like this.

You could make the sentence more formal or noun-based, but the original is much more natural in everyday Danish.

The original sentence uses a very common spoken/written pattern:

• det er uheldigt, når ... = it is unfortunate when ...

A more noun-heavy version would sound more formal, stiff, or unnatural in ordinary conversation.

So for learners, the original structure is worth remembering as a natural Danish pattern.