Learn Hardcore Indonesian: Jangankan menulis esai panjang, mengirim PR tiga kalimat pun belum tentu ia selesaikan tepat waktu. - Let alone writing a long essay, she/he might not even finish turning in three sentences of homework on time.

Jangankan menulis esai panjang
= Let alone writing a long essay (X: the harder/bigger task)
mengirim PR tiga kalimat pun belum tentu ia selesaikan tepat waktu
= even turning in a three‑sentence homework assignment, it’s not even certain that he’ll finish it on time (Y: the easier/smaller task)

So the idea is:

If even the easy thing (Y) is not certain, then of course the harder thing (X) is impossible or unrealistic.

You almost always see jangankan followed by a contrastive second part with pun or saja emphasising “even”:

Jangankan beli mobil, makan enak saja susah.
Let alone buying a car, even eating well is hard.

What is the role of pun in “PR tiga kalimat pun”?

Pun here is an emphatic particle meaning roughly “even”.

PR tiga kalimat pun ≈ “even a three‑sentence homework assignment”

It emphasizes that the second item is very small or easy, so failing at that is especially striking. In this pattern:

X = “menulis esai panjang” (a big task)
Y pun = “PR tiga kalimat pun” (even a tiny task)

Compare:

Dia belum tentu datang.
= He might not come.
Dia pun belum tentu datang.
= Even he might not come. (emphasis)

In everyday speech, pun is often replaceable by saja or aja with a similar nuance:

PR tiga kalimat saja belum tentu…
He might not even manage a three‑sentence homework…

What does belum tentu mean, and why not just say tidak?

Belum tentu literally: “not yet certain”, and idiomatically:

belum tentu ≈ not necessarily / may not / it’s not guaranteed

So:

mengirim PR tiga kalimat pun belum tentu ia selesaikan tepat waktu
≈ even a three-sentence homework isn’t certain that he’ll get it done on time
(i.e. he may well fail to do it on time)

If you use tidak instead:

… PR tiga kalimat pun tidak ia selesaikan tepat waktu.
= he did not finish even a three-sentence homework on time (more definite, factual failure)

Belum tentu suggests possibility / uncertainty, not a hard fact, which makes the sentence sound more like a general judgment about his reliability rather than a report about one specific instance.

Why is the subject “ia” only in the second part and not repeated in “Jangankan menulis esai panjang …”?

In Indonesian, once the subject is clear from context, it’s very common to omit it in subsequent clauses.

The understood subject for the whole sentence is “ia”:

(Ia) jangankan menulis esai panjang,
(ia) mengirim PR tiga kalimat pun belum tentu (ia) selesaikan tepat waktu.

Repeating ia every time would sound heavy and unnatural in this structure. The first ia is simply dropped because it’s obvious the same person is being talked about.

You could grammatically say:

Jangankan ia menulis esai panjang, mengirim PR tiga kalimat pun…

but it sounds clumsy and is not how native speakers normally phrase this pattern. The natural way is exactly as in your sentence.

What is PR, and why is it written in capitals?

PR is an abbreviation for “pekerjaan rumah”, literally “house work”, but in school context it means “homework”.

PR = school homework
It’s almost always written as PR (uppercase letters), not Pr or pr.

Synonyms or related words you might also see:

tugas rumah – homework / take‑home assignment
tugas sekolah – school assignment (not necessarily at home)
tugas – assignment in general

In everyday speech, students almost always just say PR:

Aku belum ngerjain PR.
= I haven’t done my homework yet.

Why are there two verbs, “mengirim” and “selesaikan”, in the second part? What’s going on with the structure?

The second part looks like:

mengirim PR tiga kalimat pun belum tentu ia selesaikan tepat waktu

Here’s what’s happening:

mengirim PR tiga kalimat functions as a minimal “task” description:
“the act of sending in a three-sentence homework.”
belum tentu ia selesaikan tepat waktu means
“it’s not certain that he will complete (it) on time.”

The direct object of selesaikan is understood rather than explicitly stated:

Full form (more explicit):
Mengirim PR tiga kalimat pun belum tentu ia bisa selesaikan (tepat waktu).
(Even sending in a three-sentence homework might not be something he can complete on time.)

Indonesian often drops repeated objects or replaces them with an implied “that” (itu) when context is clear.

So you can mentally read:

… belum tentu ia selesaikan (tugas itu) tepat waktu.
= … it’s not sure he’ll get that task done on time.

Why is it “ia selesaikan” and not “ia menyelesaikan”?

Both ia selesaikan and ia menyelesaikan are possible in Indonesian, but they differ slightly in flow and emphasis.

menyelesaikan = the usual me- verb “to finish/complete (something)”
selesaikan (without me-) here is a bare verb base with the -kan suffix, used especially when the object is fronted or understood from context.

In sentences where the object is placed earlier or is understood, Indonesian often drops the me- prefix:

PR itu sudah saya kerjakan. (not mengerjakan)
Masalah ini akan kita selesaikan. (not menyelesaikan)

Similarly, here:

… belum tentu ia selesaikan (tepat waktu).

Using ia menyelesaikan would push you toward a clearer, explicit object right after it:

… belum tentu ia menyelesaikan PR itu tepat waktu.

Your sentence uses a more compact, slightly formal/literary style by:

Mentioning the “task” earlier: mengirim PR tiga kalimat
Using selesaikan without me- when referring back to that task.

What nuance does “PR tiga kalimat” have? Is it “three pieces of homework” or “homework of three sentences”?

“PR tiga kalimat” is understood as:

“homework (that is only) three sentences long”

So it’s one homework assignment, and it consists of just three sentences. The point is that it’s extremely short and therefore should be easy, which makes his unreliability more striking.

If you wanted to say “three homework assignments,” you would normally say:

tiga PR or tiga tugas PR

So:

PR tiga kalimat = one assignment, length-based description
tiga PR = three separate assignments

How do we know this sentence is about general tendency (habit) rather than one specific event? Indonesian has no tense markers here.

Indonesian doesn’t inflect verbs for tense, so you rely on context and adverbs to infer time and aspect.

In this sentence:

The structure jangankan … pun belum tentu and the absence of a specific time expression (kemarin, tadi, besok, etc.) make it sound like
a general comment on someone’s usual behavior or reliability, not one single occurrence.
tepat waktu (on time) also often appears in general descriptions of someone’s habits.

If you wanted to make it clearly past tense for a specific occasion, you’d usually add a time marker:

Kemarin, mengirim PR tiga kalimat pun belum tentu ia selesaikan tepat waktu.
= Yesterday, he might not even have managed to finish a three-sentence homework on time.

Without such markers, the natural reading is habitual / general tendency.

What’s the difference between ia and dia here?

Both ia and dia mean “he/she” (third person singular without gender).

ia
- More formal, often in written Indonesian (articles, essays, stories).
- Rare in casual conversational speech.
dia
- More neutral / colloquial, common in everyday speech and informal writing.

You could very naturally say:

… belum tentu dia selesaikan tepat waktu.

That would sound more typical in spoken language. Using ia gives the sentence a slightly more literary or written tone.

Is jangankan always used with negative situations? Can it be positive?

Jangankan is strongly associated with negative or “can’t even …” type statements. Most of the time, it’s used to highlight inability, difficulty, or improbability:

Jangankan beli mobil, bayar kos saja susah.
Let alone buying a car, even paying the rent is hard.
Jangankan menulis buku, baca satu artikel penuh saja jarang.
Let alone writing a book, he rarely even reads one full article.

In practice, it almost always introduces something that doesn’t or can’t happen, followed by an even smaller thing that also doesn’t or might not happen.
Using it for purely positive statements would sound odd or sarcastic.

Could I also say “Jangankan menulis esai panjang, PR tiga kalimat saja belum tentu ia selesaikan tepat waktu”? What’s the difference with pun?

Yes, that sentence is perfectly natural:

PR tiga kalimat saja belum tentu ia selesaikan tepat waktu.

saja and pun are close here:

pun — a bit more formal/literary emphasis on “even”
saja — more colloquial, very common in speech

Nuance is very similar:

PR tiga kalimat pun belum tentu…
PR tiga kalimat saja belum tentu…

Both mean: He might not even manage a homework of just three sentences…

So your alternative with saja is fine, just a bit more casual in tone.