Tom kan niet fietsen, want zijn band is lek.

Because kan is a modal verb meaning can.

In Dutch, when you use a modal verb like kunnen (can / to be able to), the main verb usually stays in the infinitive:

• Tom kan fietsen = Tom can ride a bike / Tom can cycle
• Tom kan niet fietsen = Tom cannot ride a bike / Tom cannot cycle

So:

• kan = finite verb, conjugated for Tom
• fietsen = infinitive, placed later in the clause

If you said Tom fietst niet, that would mean Tom is not cycling or Tom does not cycle, which is a different idea.

In this sentence, niet negates the verb phrase kan fietsen.

With a modal verb, Dutch often places niet before the infinitive at the end:

• Tom kan niet fietsen

This is very natural Dutch word order.

Compare:

• Hij wil niet komen = He does not want to come
• Zij mag niet zwemmen = She is not allowed to swim

So here niet is not directly negating Tom or his tire; it is negating the action: he cannot cycle.

Because Dutch main clauses often put the conjugated verb in second position, while an infinitive linked to a modal verb goes later, often near the end.

Structure:

• Tom = subject
• kan = conjugated verb in second position
• niet fietsen = rest of the verbal part

So Dutch says:

• Tom kan niet fietsen

This is a very common pattern:

• Ik wil Nederlands leren
• We moeten nu gaan
• Zij kan goed zingen

Want means because.

So:

• Tom kan niet fietsen, want zijn band is lek.
• Tom can't cycle, because his tire is flat.

A very important thing for learners: want does not change the word order of the clause after it. The clause after want keeps normal main-clause order:

• want zijn band is lek

Compare that with omdat:

• Tom kan niet fietsen, omdat zijn band lek is.

Both mean because, but the word order is different.

Both can mean because, but they behave differently.

With want, the following clause has normal main-clause word order:

• Tom kan niet fietsen, want zijn band is lek.

With omdat, the following clause is a subordinate clause, so the verb usually goes to the end:

• Tom kan niet fietsen, omdat zijn band lek is.

In everyday speech, both are common. A rough guide:

• want often sounds a little more like giving an explanation in conversation
• omdat is also very common and often feels a bit more tightly connected grammatically

For a beginner, the main thing to remember is the word order difference.

Here band means tire.

So:

• zijn band = his tire

Be careful: band can mean several different things in Dutch depending on context, for example:

• tire
• band (music group)
• bond / connection / relationship
• ribbon / strap / belt in some contexts

In this sentence, because we are talking about cycling, band clearly means tire.

Lek means leaking or punctured / flat depending on context.

With a tire, lek is usually translated naturally as:

• flat
• punctured

So:

• zijn band is lek = his tire is flat

Literally, it is more like his tire is leaking.

You may also hear:

• een lekke band = a flat tire

Notice the adjective form:

• de band is lek
• een lekke band

The -e appears when the adjective comes before the noun.

Zijn band is the normal, natural way to say his tire.

Dutch often uses possessive words like:

• mijn = my
• jouw / je = your
• zijn = his
• haar = her
• ons / onze = our

So:

• zijn band = his tire

You can say something like de band van hem, but that is less normal here and usually only used when you want extra emphasis or clarification.

In this sentence, zijn is understood as his, referring to Tom.

Dutch zijn can sometimes refer to a masculine or neuter noun in other contexts, but here the meaning is clear:

• Tom ... zijn band = Tom ... his tire

So a learner should read it simply as his here.

Dutch has a very common specific verb for cycling: fietsen.

So Dutch often says:

• Ik fiets = I cycle / I ride a bike
• Tom kan niet fietsen = Tom can't cycle / Tom can't ride a bike

English often uses ride a bike, but Dutch very naturally uses the single verb fietsen.

If you want to be more explicit, Dutch can also say:

• fiets rijden is not standard here
• op de fiets gaan = go by bike
• fietsen op straat = cycle on the street

For this sentence, fietsen is exactly the right everyday verb.

Not necessarily.

By itself, Tom kan niet fietsen could mean:

1. Tom does not know how to ride a bike
2. Tom is unable to cycle right now

But the second clause explains the reason:

• want zijn band is lek = because his tire is flat

So in this sentence, the meaning is clearly Tom can't cycle right now because the tire is flat, not that he never learned.

Context matters a lot.

Because Dutch is not saying he has a flat tire here. It is saying:

• his tire is flat

That structure is:

• zijn band = his tire
• is = is
• lek = flat / punctured

So Dutch chooses a predicate-adjective structure, just like English can:

• His tire is flat

Another possible Dutch sentence would be:

• Tom kan niet fietsen, want hij heeft een lekke band.
• Tom can't cycle, because he has a flat tire.

That is also very common.

Both are correct and natural.

• zijn band is lek = his tire is flat
• hij heeft een lekke band = he has a flat tire

The second one is probably a little more common in everyday speech, because it is a very fixed expression:

• een lekke band hebben = to have a flat tire

But the version in your sentence is perfectly normal and easy to understand.

Quite natural. In speech, it may sound something like:

• Tom kan niet fietsen, want z'n band is lek.

Here z'n is a common spoken/written informal reduction of zijn.

So you may see:

• zijn band in careful standard writing
• z'n band in more informal writing or to reflect speech

Both mean the same thing here.