Learn Hardcore Indonesian: Anak perempuan itu cepat mencari jawaban, sedangkan anak laki-laki menunggu keterangan dari guru. - That girl quickly looks for the answer, while the boy waits for an explanation from the teacher.

itu is a demonstrative that often works like English “the/that,” pointing to a specific, known referent. So anak perempuan itu = “that/the girl (already known in context).”
Not using itu with anak laki-laki leaves it less specific; it could be “a boy” or “the boy(s)” depending on context.
You can put itu on both if both are specific: Anak perempuan itu …, sedangkan anak laki-laki itu …
More formal: tersebut (e.g., anak perempuan tersebut). Nearness: ini (this).

Is anak laki-laki singular or plural here? How do I show number in Indonesian?

Indonesian doesn’t mark number on nouns by default, so anak laki-laki can be singular or plural from context.

To make it clearly singular: seorang anak laki-laki (“a boy”) or anak laki-laki itu (“the boy”).
To make it clearly plural:
- anak-anak laki-laki (“boys”)
- beberapa anak laki-laki (“several boys”)
- With human groups you can also use para, but it’s more natural with nouns like para siswa (“the students”) than with anak.

Why is there a comma before sedangkan, and when should I use sedangkan instead of sementara?

A comma is normally placed before sedangkan because it introduces a contrasting clause.
sedangkan = “whereas,” highlighting contrast between two subjects/situations, often in the same timeframe.
- Example: Ayah bekerja di kantor, sedangkan ibu bekerja di rumah.
sementara = “while (during),” focusing on simultaneity; it can be neutral, not necessarily contrasting.
- Example: Saya membaca sementara menunggu bus.
In your sentence, sedangkan is right because it contrasts the girl’s action with the boy’s.

Can I start a sentence with sedangkan?

Yes, if it contrasts with what was said just before:

Sedangkan anak laki-laki menunggu keterangan dari guru. This is more natural when it clearly refers back to a previous clause/sentence. For a neutral “meanwhile,” you can also use Sementara itu, …

Is cepat mencari jawaban the same as mencari jawaban dengan cepat?

Close, but there’s a nuance:

cepat mencari jawaban can suggest a tendency or readiness to act quickly (quick to start/do it).
mencari jawaban dengan cepat describes the manner (the searching itself is done quickly). Other handy options:
segera mencari jawaban = immediately sets about looking.
cepat-cepat mencari jawaban = hurriedly, with urgency.
langsung mencari jawaban = straight away, without delay.

Why jawaban and not jawab? How do jawaban and menjawab relate?

Root: jawab (“answer” as a base form).
Verb: menjawab = “to answer.”
Noun: jawaban = “an/the answer.” That’s why mencari jawaban (“look for an answer”) is correct. Using mencari jawab is not natural in standard Indonesian.

What exactly does keterangan mean here? Would penjelasan be more natural?

keterangan = explanation/statement/information, often used in formal/official contexts (e.g., statements to authorities, form fields).
penjelasan = “explanation,” very common in everyday and classroom contexts.
informasi = “information,” general. In a school setting, penjelasan may feel a bit more natural; keterangan is still correct and slightly more formal.

Why dari guru and not kepada guru? Which preposition goes with menunggu?

menunggu takes a direct object (no preposition): menunggu keterangan, menunggu bus, menunggu dia.
If you add who it’s from, use dari (“from”): menunggu keterangan dari guru.
kepada = “to (someone)” and doesn’t go with menunggu here.

Does menunggu need a preposition like “for,” as in “wait for”?

No. In Indonesian, menunggu directly takes its object:

menunggu kamu (wait for you)
menunggu jawaban (wait for an answer) Optionally add the source with dari: menunggu jawaban dari guru.

How do I mark past, present, or future in this sentence?

Indonesian uses time words and aspect markers instead of verb tenses:

Past/completed: tadi, kemarin, sudah (already)
- Anak perempuan itu tadi segera mencari jawaban…
Progressive/ongoing: sedang
- … sedang menunggu keterangan dari guru.
Future/intended: akan, nanti
- … akan menunggu keterangan dari guru nanti. Context also supplies time.

Do I need yang after anak perempuan itu?

No. Here, anak perempuan itu is the subject and cepat mencari jawaban is the predicate.

If you say anak perempuan yang cepat mencari jawaban, that’s a noun phrase (“the girl who is quick to look for answers”) and you still need a main predicate after it.

Can I put cepat after the verb, like mencari cepat jawaban?

Not like that. Options that sound natural:

cepat mencari jawaban (pre-verbal)
mencari jawaban dengan cepat (use dengan
- adjective for adverbial meaning) Avoid mencari cepat jawaban.

What about more casual alternatives?

Cewek itu cepat cari jawaban, sedangkan cowoknya nunggu penjelasan dari guru.
- cewek/cowok = informal “girl/guy”
- cari for mencari, nunggu for menunggu
In polite or formal contexts, stick with anak perempuan / anak laki-laki, mencari, menunggu.

Is the hyphen in laki-laki required?

Yes. laki-laki is a reduplication form and should be hyphenated in standard writing. Similarly, plural reduplication uses a hyphen: anak-anak.

Could I use tetapi or namun instead of sedangkan?

tetapi/namun = “but/however,” general contrast, often starting a new sentence or clause: … Tetapi/Namun, anak laki-laki…
sedangkan specifically contrasts two subjects/situations, often in parallel: X …, sedangkan Y … All three can work, but sedangkan is ideal for side-by-side contrast between actors as in your sentence.

Does jawaban need -nya (jawabannya) to mean “the answer”?

Not necessarily. jawaban can be definite from context. Use -nya when referring to a specific, previously mentioned answer:

mencari jawabannya = look for that particular answer (already known in context). Without -nya, it can be generic or contextually definite.