Learn Hardcore Indonesian: Botol air mineral itu ditaruh di meja manajer. - That bottle of mineral water is placed on the manager’s table.

Yes. The verb ditaruh is the passive form of the root taruh “to put/place.” The passive is marked with the prefix di- attached to the verb, and the grammatical subject is the thing being acted upon (here, the bottle). In English it corresponds to “was put/placed.”

What’s the difference between di- in ditaruh and di in di meja?

di- (no space) is a prefix that makes a verb passive: di
- taruh → ditaruh “is/was placed.”
di (with a space) is a preposition meaning “at/in/on,” as in di meja “on/at the table/desk.” Tip: If there’s a space after di, it’s a preposition; if it’s glued to a verb, it’s the passive prefix.

How would I say this in the active voice?

Use menaruh (active) and make the agent the subject:

Sekretaris menaruh botol air mineral itu di meja manajer. “The secretary put the bottle of mineral water on the manager’s desk.” You can replace the agent with any subject (e.g., Dia menaruh… “He/She put…”).

How do I include who did the action in the passive?

Add an agent with oleh (formal/neutral) or sama (informal):

Formal: Botol air mineral itu ditaruh oleh sekretaris di meja manajer.
Informal: Botol air mineral itu ditaruh sama sekretaris di meja manajer. In everyday speech the agent is often omitted if it’s obvious or unimportant.

Does di meja mean “on the table/desk” or “at the table/desk”? What about di atas meja?

di meja commonly means “on the table/desk,” and context makes the surface reading clear.
If you want to be explicit about “on top of,” say di atas meja.
di meja can also mean “at the table” with activities like eating or meeting; with an object like a bottle, the surface sense is usually intended.

What exactly does itu mean after the noun phrase?

Post-nominal itu means “that” (deictic) or functions like a definite marker “the (one we both know).” So botol air mineral itu is “that bottle of mineral water” or “the bottle of mineral water (already known in context).” The counterpart for “this” is ini: botol air mineral ini.

Can I put itu before the noun phrase, like itu botol air mineral?

Normally, demonstratives come after the noun: botol air mineral itu. Pre-nominal itu can appear for topicalizing or pointing something out in speech (e.g., Itu, botol air mineralnya…), but as a plain noun phrase “that bottle of mineral water,” post-nominal itu is the standard choice.

Is an article like “a” or “the” required in Indonesian? How do I say “a bottle” vs “the bottle”?

Indonesian has no articles. Use other means:

Indefinite/quantity: sebotol air mineral “a bottle of mineral water,” or satu botol air mineral “one bottle…”
Definite/known: botol air mineral itu “that/the bottle of mineral water.” Your sentence is definite because of itu.

Why not say sebotol air mineral here? What’s the difference from botol air mineral itu?

sebotol air mineral emphasizes quantity (a single bottle), not which specific bottle.
botol air mineral itu points to a specific, identifiable bottle (that one/the one we’ve mentioned). Choose based on whether you want quantity or definiteness.

Does meja manajer mean “the manager’s desk”? Is this how possession works?

Yes. Noun–noun sequences express possession or classification, with the head first:

meja manajer = “manager’s desk/table.” You can make it definite: meja manajer itu “that/the manager’s desk.” Alternatives:
meja kerja manajer “the manager’s work desk” (more specific).
meja milik manajer (more explicit/formal “desk owned by the manager”).

Is ditaruh the best verb here? What about diletakkan, ditempatkan, or disimpan?

ditaruh = everyday, neutral “put/placed.”
diletakkan = a bit more formal/literary “placed/set down,” equally fine.
ditempatkan = “to be placed/assigned/positioned,” more formal and often used for people or items in planned positions; sounds bureaucratic for a bottle.
disimpan = “stored/put away,” implies keeping something for later rather than just setting it down.

Does the sentence indicate past or present? How do I show time or a current state?

Indonesian verbs don’t change for tense. ditaruh can be “is put/being put/was put,” depending on context. Add time markers if needed:

Past/completed: sudah/tadi (e.g., sudah ditaruh).
Future: akan. To state location as a current state (not an action), use:
Botol air mineral itu ada di meja manajer. “The bottle is on the manager’s desk.”

Can I move di meja manajer to the front?

Yes, for topicalization or emphasis:

Di meja manajer, botol air mineral itu ditaruh. This is grammatical but more marked; the default, most neutral order is what you have: Subject + Passive Verb + Location.