jeoneun sueop yeongsangeul bomyeonseo memohaeyo.

저는 is the polite form of 나는.

• 저 = I in polite speech
• 는 = topic marker

So 저는 means something like as for me, I...

Why not the others?

• 나는: same grammar, but less polite because 나 is the plain form of I
• 제가: uses the subject marker 가, which often puts more focus on I as the subject

In a neutral polite sentence like this, 저는 is very natural.

수업 영상 is a noun phrase made of two nouns:

• 수업 = class, lesson
• 영상 = video

Together, 수업 영상 means class video, lesson video, or video of a lesson.

This kind of noun + noun combination is very common in Korean.

-을/를 is the object marker.

Here, 영상 is the thing being watched:

• 영상을 보다 = to watch a video

Because 영상 ends in a consonant, it takes -을, so:

• 영상 + 을 → 영상을

보면서 comes from:

• 보다 = to watch / to see
• -면서 = while doing, as one does

So 보면서 means while watching.

In this sentence, it connects two actions happening at the same time:

• watching the class video
• taking notes

So the structure is basically:

A-면서 B = do B while doing A

Because -면서 attaches to the verb stem.

• dictionary form: 보다
• verb stem: 보-
• 보 + 면서 → 보면서

So 보면서 is the correct form.

Yes. A very important one: the two actions usually have the same subject.

So in this sentence, the person who is watching the video is also the person taking notes.

That is why this sentence works naturally:

• 저는 수업 영상을 보면서 메모해요.

Both actions are done by 저.

Both are correct.

• 메모해요
• 메모를 해요

메모하다 is a common noun + 하다 verb.

In Korean, with many 하다 verbs, the object marker -를 is often omitted, especially in everyday speech.

So:

• 메모를 해요 = more explicitly do notes / take notes
• 메모해요 = more natural and compact in many situations

Usually yes in this kind of sentence.

메모하다 literally means to make a memo / write something down / take notes.

Depending on context, it can mean:

• to jot something down
• to make a note
• to take notes

Here, take notes is the most natural translation.

-해요 is the polite informal ending, often called the -요 style.

So 메모해요 means:

• I take notes
• I’m taking notes
• I take notes while...

It is polite and very common in daily conversation.

If you made it more formal, you could say:

• 메모합니다

If you made it plain/casual, you could say:

• 메모해

It can feel like either one in English, depending on context.

메모해요 is a non-past form, so it can mean:

• I take notes while watching class videos (habit)
• I’m taking notes while watching the class video (right now / current situation)

Korean often leaves that distinction to context.

It can be either.

Korean usually does not mark singular vs. plural unless it needs to.

So 수업 영상을 보면서 could mean:

• while watching the class video
• while watching class videos

You understand the number from context.

Sometimes, yes.

For example, in casual conversation, someone might say:

• 저는 수업 영상 보면서 메모해요.

Here, -을 is omitted from 영상(을).

This is common in speech, but for learners, using the particle is a good habit because it makes the grammar clearer.

So the full sentence with 영상을 is perfectly good and natural.