Menjelang ujian matematika, saya membaca ulang catatan di perpustakaan.

Menjelang functions like a preposition meaning approaching / leading up to an event. It emphasizes that the time is close to the exam period.

• Menjelang ujian = in the period right before the exam (the exam is coming soon)
• Sebelum ujian = anytime before the exam (could be far earlier too)

So menjelang is more specific and “nearer” in time than sebelum.

The comma is used because Menjelang ujian matematika is a fronted time phrase (a sentence opener). The comma is common and helps readability, especially in writing.

• It’s often optional in informal writing, but it’s a good habit in more formal writing. You could also write it without a comma and it would still be understood.

No—Menjelang ujian matematika is a phrase, not a full clause (it has no subject/verb). Indonesian often uses time phrases directly without a word like when. You can add something like:

• Menjelang ujian matematika, ... (natural, common)
• Ketika menjelang ujian matematika, ... (possible but often feels heavier/more formal)

Indonesian noun phrases typically put the main noun first and the specifier after it.

• ujian = the main noun (exam)
• matematika = specifies what kind of exam (math) So ujian matematika = math exam.

membaca ulang literally means to read again / reread. It’s two words because:

• membaca = to read
• ulang = again/repeat Indonesian often expresses “re-” ideas (like reread) with a separate word like ulang rather than a prefix.

membaca is the standard active verb form in formal/neutral Indonesian.

• Root: baca (read)
• With meN-: membaca = to read (active, doing the action)

baca alone can appear in:

• commands: Baca ini! (Read this!)
• very casual/informal styles (like notes or messaging)

They overlap, but have slightly different feel:

• membaca ulang = reread (very direct and common)
• membaca kembali = read again (also common; can sound a bit more neutral/reflective)
• mengulang = to repeat/review (broader; not limited to reading—can repeat a lesson, practice again, etc.) For “reread notes,” membaca ulang catatan is very natural.

catatan can mean note/notes depending on context. Indonesian doesn’t require plural marking. If you really want to stress plural, you can use:

• catatan-catatan (notes, multiple separate notes) But in this sentence, catatan naturally covers the idea of “my notes” as a set.

di marks location (where something happens):

• di perpustakaan = in/at the library

If you mean motion toward the library, use ke:

• ke perpustakaan = to the library

And for motion from the library, use dari:

• dari perpustakaan = from the library

Yes. Indonesian is flexible with adverbial phrases like time/place. These are all possible:

• Menjelang ujian matematika, saya membaca ulang catatan di perpustakaan.
• Saya membaca ulang catatan di perpustakaan menjelang ujian matematika. The first version foregrounds the timing (sets the scene first). The second is more straightforward “subject-first.”

Yes, you could use aku, but it changes the tone:

• saya = neutral/formal/polite (good for writing, school contexts, speaking politely)
• aku = informal/intimate (friends, personal stories, casual speech) Because this is about studying and sounds like a written sentence, saya fits well.

perpustakaan is built from the root pustaka (books/literature) plus a common noun-forming pattern:

• per- ... -an often creates a noun meaning a place/institution related to the root So perpustakaan = the place/institution related to pustaka → library.