Saya mengisi wadah minum dengan air sebelum pergi ke kantor.

The base form is isi, which is related to contents or to fill. In this sentence, mengisi is the active verb form made with the meN- prefix.

So:

• isi = content, contents, fill
• mengisi = to fill

Because this is a normal declarative sentence with an active verb, mengisi is the expected form.

In standard Indonesian, mengisi is the normal verb form for a sentence like this.

Using just isi is more natural in cases like:

• commands: Isi botol itu! = Fill that bottle!
• some informal or shortened speech

But in a full, neutral sentence, Saya mengisi ... sounds correct and natural.

The prefix meng- is one form of the meN- prefix, which commonly forms active verbs.

Here it turns isi into an active transitive verb, meaning a verb that takes a direct object:

• Saya mengisi wadah minum ...
• direct object: wadah minum

A useful point for learners: when the root begins with a vowel, meN- often appears as meng-, which is why isi becomes mengisi.

Literally, wadah minum means drinking container or container for drinking.

It is understandable, but it sounds somewhat general or descriptive. Depending on the situation, native speakers might more often say:

• botol minum = drinking bottle / water bottle
• tumbler = tumbler
• gelas = glass
• cangkir = cup

So wadah minum is not wrong, but it sounds broader and a little less specific than what people often say in daily conversation.

Yes, air in Indonesian means water, not the English word air.

This is a very common false friend for English speakers.

• Indonesian air = water
• Indonesian udara = air

Also, Indonesian air is pronounced roughly ah-eer, not like the English word air.

Dengan here means with, and it introduces what the container is being filled with:

• mengisi wadah minum dengan air = fill the drinking container with water

This structure is very similar to English.

Without dengan air, the sentence would still be grammatical:

• Saya mengisi wadah minum sebelum pergi ke kantor.

But then the specific contents are not stated. Adding dengan air makes it explicit.

That would sound less natural if your main idea is fill the container.

If the focus is the container being filled, mengisi wadah minum dengan air is the best structure.

If the focus is the action of pouring water into it, Indonesian more naturally uses a verb like:

• menuang air ke dalam wadah minum
• menuangkan air ke dalam wadah minum

So:

• mengisi wadah minum dengan air = fill the container with water
• menuangkan air ke dalam wadah minum = pour water into the container

Both are possible.

Indonesian often omits the subject in a subordinate clause when it is clearly the same as the subject of the main clause. So:

• Saya mengisi wadah minum dengan air sebelum pergi ke kantor.

is understood as:

• Saya mengisi wadah minum dengan air sebelum saya pergi ke kantor.

The shorter version sounds natural and efficient.

If you want to be extra explicit, or if there might be ambiguity, you can include saya.

Yes. Indonesian allows that very naturally.

You can say:

• Sebelum pergi ke kantor, saya mengisi wadah minum dengan air.

This puts more focus on the time setting. It means the same thing as the original sentence.

Both can work, but they have slightly different nuances.

• pergi ke kantor = go to the office
• berangkat ke kantor = leave/set off for the office

In this kind of daily routine sentence, many speakers might prefer berangkat ke kantor because it emphasizes leaving home for work. But pergi ke kantor is still correct and natural.

So the original sentence is fine, but this may sound a bit more everyday:

• Saya mengisi wadah minum dengan air sebelum berangkat ke kantor.

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

So nouns like wadah minum and kantor can mean:

• a drinking container / the drinking container
• an office / the office

The exact meaning depends on context.

If you need to make it more specific, Indonesian can use other words, such as:

• wadah minum itu = that/the drinking container
• kantor saya = my office
• sebuah wadah minum = a drinking container

Literally, kantor means office. But in context, pergi ke kantor often functions much like go to work, especially if the person works in an office.

So depending on context, English might translate it as:

• go to the office
• go to work

If you want a more general expression for workplace, Indonesian can also use tempat kerja.

Yes, often.

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

So in everyday casual speech, someone might say:

• Aku mengisi wadah minum dengan air sebelum pergi ke kantor.

That sounds natural in an informal context. The original with saya is more neutral and broadly appropriate.

Usually yes, but it depends on what you want to emphasize.

Mengisi focuses on filling the container, and it does not always have to mean filling it all the way to the top. It can simply mean putting the contents in.

But if you specifically want to emphasize the act of pouring, Indonesian might use:

• menuang
• menuangkan

So:

• mengisi wadah minum dengan air = fill the drinking container with water
• menuangkan air ke dalam wadah minum = pour water into the drinking container

Both are possible, but they highlight slightly different aspects of the action.