yaksok siganeul memojange jeonghwakhage jeogeo duseyo.

Because 시간 is the direct object of 적다 (to write down).

In this sentence, what you are writing down is the appointment time, so Korean marks 시간 with the object particle -을/-를:

• 약속 시간 = appointment time / meeting time
• 약속 시간을 = the appointment time (as the thing being written)

So the structure is basically:

• 약속 시간을 = write down the appointment time
• 메모장에 = in/on the memo pad
• 정확하게 = accurately
• 적어 두세요 = write it down and keep it noted for later

약속 means promise, but very often in everyday Korean it also means appointment, plans, or an arranged meeting.

So 약속 시간 means:

• the time of an appointment
• the agreed meeting time
• the time you promised to meet

It does not usually mean just any random time. It specifically refers to the time connected to an arrangement or commitment.

For example:

• 약속이 있어요. = I have plans / I have an appointment.
• 약속 시간을 잊었어요. = I forgot the appointment time.

Here, -에 marks the place where the writing goes.

So 메모장에 적다 means:

• write it in the memo pad
• write it on the notepad
• write it in your notes

With writing verbs, Korean often uses -에 to show the surface, place, or destination where something is written.

Examples:

• 공책에 쓰다 = write in a notebook
• 종이에 적다 = write on paper
• 메모장에 적다 = write in/on a memo pad

So 메모장에 is functioning like in the memo pad / on the memo pad.

Both can relate to writing, but they are not always identical.

• 쓰다 = to write in a broad, general sense
• 적다 = to write down, to note down, to jot down

In this sentence, 적다 sounds especially natural because the idea is to record information so you don’t forget it.

Compare:

• 편지를 쓰다 = write a letter
• 일기를 쓰다 = write a diary/journal
• 전화번호를 적다 = write down a phone number
• 약속 시간을 적다 = write down the appointment time

So 적다 fits the context of making a note better than 쓰다.

This is a very common Korean grammar pattern:

• 적다 = to write down
• 적어 두다 = to write it down and leave it that way for later

The -아/어 두다 pattern means:

• do something in advance
• complete an action and keep the result
• do something for future convenience

So 적어 두세요 is more than just please write it. It means something like:

• Please write it down ahead of time
• Please make a note of it and keep it recorded
• Please write it down so you have it later

This is why it sounds very natural in reminders, instructions, and practical situations.

Not really. Although 두다 by itself often means to put or to place, in -아/어 두다 it works as an auxiliary verb with a different function.

So in 적어 두세요, 두다 does not literally mean put. Instead, it adds the idea of:

• doing something in advance
• leaving it done
• keeping the result for later use

So you should understand 적어 두세요 as one combined expression, not as write and then put.

Yes, 정확히 is also possible.

Both of these can mean accurately or exactly:

• 정확하게
• 정확히

In many situations, they are very close in meaning.
Here, 정확하게 적어 두세요 means write it down accurately / exactly.

A learner-friendly way to think about it:

• 정확하다 = to be accurate / exact
• 정확하게 = accurately
• 정확히 = accurately / exactly

Both are natural, though 정확히 can sometimes sound a bit more compact and common in speech.

So these are both fine:

• 약속 시간을 메모장에 정확하게 적어 두세요.
• 약속 시간을 메모장에 정확히 적어 두세요.

-세요 is a polite ending used for requests, instructions, or suggestions directed to the listener.

So 적어 두세요 is:

• polite
• appropriate in everyday conversation
• commonly used by teachers, staff, parents, or anyone giving a respectful instruction

It is softer and more polite than a blunt command.

Compare:

• 적어 둬. = Write it down. (casual, to someone close or younger)
• 적어 두세요. = Please write it down. (polite)
• 적어 두십시오. = Please write it down. (more formal)

So the original sentence sounds like a polite instruction.

Yes. Korean word order is flexible as long as the particles make the roles clear.

Original:

• 약속 시간을 메모장에 정확하게 적어 두세요.

Possible rearrangements:

• 메모장에 약속 시간을 정확하게 적어 두세요.
• 약속 시간을 정확하게 메모장에 적어 두세요.

These all mean basically the same thing, but the emphasis can shift slightly depending on what comes earlier.

The original order is very natural because it presents:

1. what to write down
2. where to write it
3. how to write it
4. the action/request

That is a common and clear Korean sentence pattern.

Yes, it can mean either, depending on context.

메모장 literally means something like memo pad or note pad, but in modern Korean it can refer to:

• a physical notepad
• a memo section in a planner
• a notes app on a phone or computer

If the speaker wants to be more specific, they might say:

• 수첩에 = in a pocket notebook/planner
• 공책에 = in a notebook
• 휴대폰 메모장에 = in your phone’s memo app
• 메모 앱에 = in a memo app

So in your sentence, 메모장에 is slightly broad and practical: just note it down in your memo pad/notes.

Yes. The difference is subtle but important.

• 적으세요 = please write it down
• 적어 두세요 = please write it down and keep it recorded for later

So 적어 두세요 feels more purposeful when the note is meant to be saved, checked later, or used to avoid forgetting.

For example:

• 이 번호를 적으세요. = Please write down this number.
• 이 번호를 적어 두세요. = Please write down this number and keep it noted for later.

In your sentence, 적어 두세요 is especially natural because appointment times are something you usually record in advance so you don’t forget them.

The standard form is usually written with a space:

• 적어 두세요

That is because 두다 is functioning as an auxiliary verb attached to the main verb 적다, and Korean spelling conventions often separate it.

However, in real life you may also see:

• 적어두세요

especially in casual writing, online text, or signage.

For learning purposes, it is safest to use:

• 적어 두세요

That will look clean and standard.

It can feel like any of those depending on context, but most naturally it is a polite instruction or practical request.

For example, it could be said by:

• a teacher to students
• a receptionist to a visitor
• a parent to a child
• a coworker to another coworker

Because of -세요, it is not harsh. It sounds more like:

• Please make sure to write it down accurately
• Please note it down carefully

So grammatically it is imperative, but in tone it is polite and helpful rather than aggressive.