Kapag maraming tao sa bus, nakatayo ang ibang pasahero dahil wala nang upuan.

Kapag introduces a situation or condition. In English, it can often be translated as when or if, depending on context.

In this sentence, Kapag maraming tao sa bus... means something like:

• When there are many people on the bus...
• or If the bus is crowded...

So kapag is commonly used for general situations: whenever/when/if this happens, that happens.

In Filipino, nouns usually do not change form for singular vs. plural the way they do in English.

So:

• tao = person / people
• maraming tao = many people

The idea of plurality is already shown by marami (many), so the noun itself does not need a special plural ending.

Maraming means many or a lot of.

It comes from marami + the linker -ng:

• marami = many / numerous
• maraming tao = many people

The -ng links marami to the following word. This is very common in Filipino when one word modifies the next.

Sa is a general location marker. Here it means in/on the bus.

So:

• sa bus = on the bus / in the bus

In English we usually say on the bus, but Filipino uses sa much more broadly for location, direction, or place.

Filipino often uses a predicate-first sentence pattern.

So instead of starting with the equivalent of some passengers, Filipino often starts with the description or state:

• nakatayo = standing
• ang ibang pasahero = some of the passengers / the other passengers

Literally, the structure is closer to:

• Standing are some passengers

But natural English would be:

• Some passengers are standing

This predicate-first order is very normal in Filipino.

Nakatayo means standing in the sense of being in a standing position.

It describes a state:

• nakatayo = standing upright / is standing

By contrast, tumatayo usually means stands up or is standing up, focusing more on the action/process.

So in this sentence, nakatayo is used because the passengers are already in that position, not in the act of rising.

Ibang pasahero here means some of the passengers or other passengers.

• iba = other / different
• ibang = linked form before a noun
• pasahero = passenger

In this context, ang ibang pasahero usually means some passengers—that is, not everyone, but a portion of them.

Ang marks the topic/focus of the clause.

In nakatayo ang ibang pasahero, the phrase ang ibang pasahero is the thing being described as standing.

So:

• nakatayo = are standing
• ang ibang pasahero = some passengers

Using ng here would give a different grammatical relationship, so ang is the correct marker for the main noun phrase in this clause.

Mga is a plural marker, but it is not always required when plurality is already clear from context.

Here, plurality is already strongly suggested by:

• ibang = some/other
• the situation of a crowded bus
• the overall meaning of the sentence

So ang ibang pasahero naturally means some passengers.

You could sometimes hear ang ibang mga pasahero, but mga is not necessary here.

Dahil means because.

It introduces the reason:

• dahil wala nang upuan = because there are no more seats

So the sentence has this structure:

• When the bus is crowded, some passengers stand because there are no more seats.

Wala is used to express non-existence or absence:

• wala = there is none / there is not any

So:

• wala nang upuan = there are no more seats

By contrast, hindi is used to negate verbs, adjectives, or statements:

• hindi siya nakatayo = he/she is not standing

Since the sentence is talking about the absence of seats, wala is the correct choice.

Here, nang means something like already or any more in English, depending on translation.

So:

• wala nang upuan = there are no more seats / there aren’t any seats left anymore

This nang comes from na used in a form that connects smoothly after wala.

The important idea is that the bus may have had seats available before, but now none are left.

Like many Filipino nouns, upuan does not have to change form for plural.

So:

• upuan = seat / seats, depending on context

In wala nang upuan, the meaning is clearly plural in English:

• there are no more seats
• there are no seats left

Context tells you that it refers to available seating in general, not just one single seat.

Upuan literally refers to something you sit on, such as a seat or chair.

In the context of a bus:

• upuan = seat

So wala nang upuan specifically means there are no seats available anymore.

Yes. In everyday speech, kapag is often shortened to pag.

So you may hear:

• Pag maraming tao sa bus, nakatayo ang ibang pasahero...

This is very common and natural in conversation.
However, kapag is a bit fuller and often preferred in more careful or formal writing.

It most naturally describes a general situation or a usual pattern.

That is because of:

• kapag = when/whenever
• the overall structure of cause and effect

So the sense is:

• Whenever a bus is crowded, some passengers have to stand because there are no seats left.

If you wanted to talk about one specific event, Filipino would likely use a different setup with more specific time reference.

Yes. A natural English translation would be something like:

• When the bus is crowded, some passengers have to stand because there are no seats left.
• When there are many people on the bus, some passengers stand because there are no more seats.

A more literal breakdown is:

• Kapag = when/if
• maraming tao sa bus = there are many people on the bus
• nakatayo ang ibang pasahero = some passengers are standing
• dahil wala nang upuan = because there are no more seats

So the natural translation may be smoother than the literal one, but both reflect the same grammar.