Jeg må skynde mig til stationen, hvis jeg skal nå toget.

Here må means must or have to.

It is the present tense of the modal verb måtte. In Danish, må can mean two main things:

• must / have to
• may / be allowed to

In this sentence, the context clearly gives the must / have to meaning:

• Jeg må skynde mig = I must hurry

The second part, hvis jeg skal nå toget, shows necessity, so may would not fit here.

Because skynde sig is a reflexive verb in Danish.

That means the verb normally goes with a reflexive pronoun:

• jeg skynder mig
• du skynder dig
• han/hun skynder sig
• vi skynder os

So in this sentence:

• Jeg må skynde mig = I must hurry

The mig refers back to jeg. English usually just says hurry, but Danish commonly uses skynde sig.

Because mig is the object/reflexive form that matches jeg.

Compare:

• jeg = I
• mig = me

Since skynde sig needs a reflexive object, jeg becomes mig:

• Jeg skynder mig

You cannot say Jeg skynder jeg.

They do different jobs.

• må in the main clause expresses necessity: I must / I have to
• skal in the hvis-clause expresses what is required for the result: if I am going to / if I am to / if I’m to

So the structure is roughly:

• Jeg må skynde mig = I must hurry
• hvis jeg skal nå toget = if I’m going to catch the train

A useful way to feel the difference is:

• må = my immediate necessity
• skal = the condition tied to the goal

Because after a modal verb in Danish, the next verb is usually in the bare infinitive, without at.

That applies to verbs like:

• må
• skal
• kan
• vil
• bør

So:

• jeg må skynde mig
• jeg skal nå toget

Not:

• jeg må at skynde mig
• jeg skal at nå toget

This is very similar to English, where we say must hurry, not must to hurry.

Because til is used for movement toward a place: to the station.

Here the speaker is going in the direction of the station, so:

• til stationen = to the station

If the idea were being at the station, Danish would often use something else, depending on context, such as på stationen.

So the choice of til tells you this is about motion.

Both mean the noun, but Danish puts the definite article at the end of the noun, and the ending depends on the noun’s gender.

• station → stationen = the station
• tog → toget = the train

Very roughly:

• common gender nouns often take -en
• neuter nouns often take -et

So this sentence shows two definite nouns:

• stationen = the station
• toget = the train

Hvis means if.

It introduces a condition:

• hvis jeg skal nå toget = if I’m going to catch the train

It is used because catching the train is presented as the condition that makes hurrying necessary.

A learner often compares hvis and når:

• hvis = if
• når = when

Here hvis is right because the sentence is conditional, not simply about a certain future event.

Here nå toget means catch the train or make the train.

The verb nå often means:

• reach
• get to
• make it in time
• catch, depending on context

So although the literal idea is something like reach the train, the natural meaning in this sentence is catch the train in time.

That is why nå toget sounds natural in Danish.

Yes:

• Hvis jeg skal nå toget, må jeg skynde mig til stationen.

That is completely natural.

But notice the word order in the main clause after the fronted clause:

• må jeg
• not jeg må

This happens because Danish main clauses follow the V2 rule: the finite verb comes in second position.

So:

• Jeg må skynde mig ..., hvis ...
• Hvis ..., må jeg skynde mig ...

Both are correct, but the word order changes when the sentence starts with the hvis-clause.

Because hvis jeg skal nå toget is a subordinate clause.

In Danish, many writers place a comma before a subordinate clause like this. So:

• Jeg må skynde mig til stationen, hvis jeg skal nå toget.

You may also see Danish written without that comma, depending on the comma system being used. Both styles can occur, but the sentence you were given uses the version with the comma before the subordinate clause.