Sofie draagt de zware tas niet op één arm, omdat haar nek dan pijn doet.

Because the subject is Sofie, which is third person singular (she).

The verb dragen means to carry / to wear. In the present tense:

• ik draag
• jij draagt
• hij/zij draagt
• wij dragen

So with Sofie, you use draagt.

In Dutch, adjectives usually take -e when they come before a noun with de.

So:

• de zware tas = the heavy bag
• het zware boek = the heavy book

Here, tas is a de-word, so the adjective becomes zware.

This is a very common pattern:

• de grote auto
• de mooie tafel
• de zware tas

Yes, tas is a de-word: de tas.

Unfortunately, grammatical gender in Dutch often just has to be learned with the noun. English speakers usually need to memorize nouns together with their article:

• de tas
• de nek
• de arm

That also helps with adjective endings and pronouns later.

It means on one arm or more naturally in English, carrying it with one arm / over one arm.

In Dutch, op is often used in expressions about how something is physically supported or carried.

So de tas op één arm dragen means she is carrying the bag using just one arm, rather than balancing it in some other way.

Because één means the number one, while een without accents usually means a/an.

So:

• een tas = a bag
• één arm = one arm

The accents show that the word is stressed and numerical. They help avoid confusion.

Because niet is negating the way she carries the bag.

The idea is:

• she does carry the bag,
• but not on one arm.

So niet comes before the phrase it is affecting:

• Sofie draagt de zware tas niet op één arm.

If you move niet, the emphasis can change, and some positions sound less natural.

A useful way to understand this sentence is:

• She does not carry the heavy bag on one arm

rather than

• She does not carry the heavy bag at all

So the negation focuses on op één arm.

Omdat means because.

It introduces a subordinate clause that gives the reason:

• Sofie draagt de zware tas niet op één arm
• omdat haar nek dan pijn doet

So the second part explains why she does not carry it that way.

Dutch learners should pay special attention to omdat, because it changes the word order in the clause that follows.

Because after omdat, Dutch uses subordinate clause word order, where the verb usually goes to the end.

The main clause pattern is often:

• subject + verb + ...

But after omdat, the finite verb moves to the end:

• omdat haar nek dan pijn doet

Compare:

• Main clause: Haar nek doet dan pijn.
• Subordinate clause: ... omdat haar nek dan pijn doet.

So doet has to come at the end here.

Here dan means then or in that case.

It refers to the consequence if she carries the bag on one arm:

• ... because her neck then hurts
• more natural English: ... because her neck hurts if she does that

So dan points to a result in that situation.

It does not mean than here. Dutch dan can mean both than and then, depending on context.

Dutch very often uses the expression pijn doen for a body part:

• Mijn rug doet pijn = My back hurts
• Zijn hoofd doet pijn = His head hurts
• Haar nek doet pijn = Her neck hurts

This is the normal, everyday way to say that a body part hurts.

You can say things with pijnlijk, but that is often less neutral or less common in everyday speech. For a learner, X doet pijn is the most useful pattern to remember.

Dutch usually uses a possessive determiner here, just like English:

• haar nek = her neck

This is much more natural than de nek van haar in a normal sentence.

So for body parts, Dutch commonly says:

• mijn hand
• zijn rug
• haar nek

even when English might sometimes phrase things differently.

Yes. Dragen is used for both meanings, depending on context.

For example:

• Zij draagt een tas. = She carries a bag.
• Zij draagt een jas. = She wears a coat.

In your sentence, because the object is de zware tas and there is op één arm, the meaning is clearly carry.

Because the sentence has a main clause followed by a subordinate clause introduced by omdat.

So Dutch normally writes:

• Sofie draagt de zware tas niet op één arm, omdat haar nek dan pijn doet.

The comma helps show the break between the main statement and the reason.

Yes, but the grammar and tone are a little different.

With want (because / for), the following clause keeps main clause word order:

• Sofie draagt de zware tas niet op één arm, want haar nek doet dan pijn.

With omdat, the verb goes to the end:

• Sofie draagt de zware tas niet op één arm, omdat haar nek dan pijn doet.

Both are possible, but omdat often sounds a bit more tightly connected as a reason inside the sentence, while want can feel a bit more like an added explanation.

Yes. It is in the present tense.

Dutch present tense can mean:

• something happening now
• something that happens regularly / usually

So this sentence could mean either:

• right now, she is not carrying it on one arm, or
• in general, she does not carry heavy bags that way

The context would tell you which is intended.