biga waseo angyeongeul dakkayagessda.

In this sentence, 비가 오다 is the normal way to say it rains / rain comes.

• 비 = rain
• 오다 = to come
• 비가 오다 = to rain

The particle -가 marks 비 as the subject of the verb 오다.
So 비가 와서 literally means something like because rain comes → more naturally, because it’s raining.

Korean often uses -가/-이 with weather expressions like this:

• 비가 오다 = to rain
• 눈이 오다 = to snow

와서 is the -아서/-어서 connective form of 오다.

• 오다 → 와서

In this sentence, -아서/-어서 expresses a reason or cause:

• 비가 와서 = because it’s raining / since it’s raining

So the sentence is structured like:

• 비가 와서 = because it’s raining
• 안경을 닦아야겠다 = I should wipe my glasses

Put together: Because it’s raining, I should wipe my glasses.

This is an irregular-looking but very common contraction.

For verbs ending in 오, when you add -아서, it usually contracts:

• 오다 + 아서 → 와서

This same pattern appears in many common forms:

• 와요 from 오다 + 아요
• 왔어요 from 오다 + 았어요
• 와서 from 오다 + 아서

So 와서 is just the natural contracted form.

It breaks down like this:

• 안경 = glasses
• -을 = object particle
• 닦다 = to wipe / clean
• -아야 하다 = have to / need to
• -겠- = speaker’s judgment, intention, or realization

So:

• 닦아야 하다 = have to wipe / need to wipe
• 닦아야겠다 = I should wipe / I guess I need to wipe / I’d better wipe

In this sentence, -아야겠다 sounds like the speaker is realizing a need and deciding to do it.

Both can relate to obligation, but the feeling is a bit different.

닦아야 해요

This means:

• I have to wipe them
• I need to wipe them

It sounds more like a straightforward obligation or necessity.

닦아야겠다

This often means:

• I should wipe them
• I’d better wipe them
• Looks like I need to wipe them

It has a stronger sense of:

• the speaker’s immediate realization
• a personal decision
• a conclusion based on the situation

So in 비가 와서 안경을 닦아야겠다, the speaker is reacting to the rain and thinking, I’d better wipe my glasses.

Korean often leaves out subjects when they are obvious from context.

In English, you usually need to say:

• I should wipe my glasses

In Korean, if it’s clear the speaker is talking about themselves, you can simply say:

• 안경을 닦아야겠다

The I is understood naturally.
This is very common in Korean conversation.

If you added a subject, it might be:

• 저는 안경을 닦아야겠어요.

But in many situations, that sounds less natural than just omitting it.

Yes. In Korean, possessive words like my, your, and his/her are often omitted when the owner is obvious.

So:

• 안경을 닦아야겠다 literally = need to wipe glasses
• natural English = I should wipe my glasses

Because the speaker is the one talking about wiping the glasses, Korean does not need to explicitly say 내 안경.

If you said 내 안경을 닦아야겠다, it is not wrong, but it may sound more emphatic than necessary in an ordinary context.

Because 안경 is the direct object of 닦다.

• 닦다 = to wipe / clean something
• the thing being wiped gets -을/를

So:

• 안경을 닦다 = to wipe the glasses

Since 안경 ends in a consonant, it takes -을, not -를.

It can mean either, depending on context.

For 안경을 닦다, common English translations are:

• wipe my glasses
• clean my glasses

The core idea is physically wiping a surface to remove water, dirt, fog, or smudges.

In this sentence, because it’s raining, wipe my glasses is especially natural.

In this sentence, it means because it’s raining.

The ending -아서/-어서 can sometimes connect actions in a sequence, but one of its most common uses is giving a reason. Here, the logic is:

• It’s raining
• therefore I should wipe my glasses

So the causal meaning is the natural one.

If someone translated it as Rain came and I should wipe my glasses, that would sound unnatural in English and would not reflect the intended Korean meaning well.

The final form 닦아야겠다 is in a plain, non-polite style. This style is often used in:

• self-talk
• diary-like thoughts
• casual speech
• narration
• quoting someone’s inner thought

So this sentence can sound like the speaker thinking to themselves:

• It’s raining, so I should wipe my glasses.

If you wanted to make it polite, you could say:

• 비가 와서 안경을 닦아야겠어요.

That would be more appropriate when speaking politely to someone.

Yes, very naturally.

Even if the meaning is already known, a learner might wonder why rain leads to wiping glasses. The implied situation is probably something like:

• raindrops got on the glasses
• the lenses became wet or smudged
• visibility got worse

Korean often leaves this kind of practical background unstated because it is easy to infer from context.

So the sentence does not explicitly say:

• My glasses got wet

but that idea is strongly implied.

Yes, but not just simple future. It usually expresses a decision or realization about what the speaker ought to do next.

So 안경을 닦아야겠다 suggests:

• I should wipe my glasses now / soon
• I’d better wipe my glasses

It points to a likely upcoming action, but the main feeling is not just future tense. It is more about the speaker concluding that the action is necessary.

So it is closer to:

• I’d better... than to a neutral future like
• I will...