Kalau hujan deras, saya naik bus ke kantor.

Here kalau introduces a condition, so it usually means if.

In this sentence, Kalau hujan deras, saya naik bus ke kantor, it means something like:

• If it rains heavily, I take the bus to the office
• or, in a habitual sense, When it rains heavily, I take the bus to the office

In everyday Indonesian, kalau can cover both if and when, depending on context.

Other words with a similar function are:

• jika — more formal, also if
• bila — also if/when, somewhat formal

Because Indonesian does not use a dummy subject like English it in weather expressions.

English says:

• It is raining
• It rains a lot

But Indonesian simply says:

• Hujan
• Sedang hujan
• Hujan deras

So hujan deras does not need a subject. It naturally means it is raining heavily or heavy rain depending on context.

This is very common in Indonesian. You do not need to add a word for it.

Because in Indonesian, descriptive words usually come after the noun or main word they describe.

So:

• hujan deras = heavy rain
• angin kencang = strong wind
• rumah besar = big house

That is the normal order.

So hujan deras is the natural Indonesian pattern, not deras hujan.

Yes. Indonesian often leaves out a verb like to be where English requires is/are.

English needs:

• It is raining heavily
• The rain is heavy

Indonesian can simply say:

• Hujan deras

This is normal and complete in context.

Indonesian does not use a present-tense to be like English in many sentences. So learners should not expect a word corresponding to is every time.

The verb naik literally means to go up, to get on, or to ride. With transportation, it often means to take/go by/ride that vehicle.

So:

• naik bus = take the bus / go by bus
• naik kereta = take the train
• naik pesawat = take the plane
• naik sepeda = ride a bicycle

In this sentence, saya naik bus ke kantor means I go to the office by bus or I take the bus to the office.

Normally, no.

Mengambil means to take in the sense of pick up, take something, or fetch, not take a bus as in transportation.

So:

• Saya mengambil buku = I take/pick up a book
• but not Saya mengambil bus for I take the bus

For transportation, Indonesian normally uses:

• naik bus
• pergi dengan bus = go by bus
• naik kendaraan umum = take public transport

So naik bus is the natural choice here.

Ke is a preposition meaning to in the sense of movement toward a place.

So:

• ke kantor = to the office
• ke sekolah = to school
• ke rumah = to home / homeward depending on context
• ke Jakarta = to Jakarta

In this sentence:

• saya naik bus ke kantor = I take the bus to the office

So ke marks the destination.

Because Indonesian does not have articles like English a/an and the.

So:

• bus can mean a bus or the bus
• kantor can mean an office, the office, or just office

The exact meaning depends on context.

In this sentence, English naturally translates it as the bus or just the bus/by bus, and the office, but Indonesian does not need separate article words.

This is a major difference from English.

Indonesian verbs do not change form for tense the way English verbs do.

So saya naik bus ke kantor can mean different things depending on context, such as:

• I take the bus to the office
• I am taking the bus to the office
• I will take the bus to the office

In this sentence, with kalau hujan deras, the most natural reading is habitual:

• If/when it rains heavily, I take the bus to the office

So it sounds like something the speaker usually does in that situation.

If you wanted to make time clearer, you could add words like:

• biasanya = usually
• sedang = in progress
• akan = will

Yes. Indonesian often allows the condition clause either at the beginning or later in the sentence.

So both of these are natural:

• Kalau hujan deras, saya naik bus ke kantor.
• Saya naik bus ke kantor kalau hujan deras.

The meaning stays basically the same.

Putting kalau hujan deras first gives more emphasis to the condition, similar to English If it rains heavily, ...

Also, the comma is helpful when the kalau clause comes first, but in informal writing people may leave it out.

Both bus and bis are used, but bus is now very common and standard in modern Indonesian.

So you may see:

• naik bus
• naik bis

Both are understood.

If you are learning standard modern Indonesian, bus is a safe choice.

Saya is the neutral and polite word for I. It works well in most situations.

• saya = neutral, polite, standard
• aku = more casual, personal, intimate

So in a general example sentence like this, saya is the most natural choice.

You could say aku naik bus ke kantor in casual speech, but it would sound more informal and personal.