biga omyeon jajeongeoreul taji malgo jihacheoreul tayo.

-면 means if or when.

So:

• 비가 오다 = to rain
• 비가 오면 = if it rains / when it rains

In Korean, -면 attaches to a verb stem to make a condition:

• 가다 → 가면 = if/when someone goes
• 먹다 → 먹으면 = if/when someone eats
• 오다 → 오면 = if/when it rains / if/when it comes

In this sentence, 비가 오면 sets the condition for the advice that follows.

Because 비가 오다 is the normal way to say it rains.

Here, 비 is the subject of the verb 오다 in the weather expression 비가 오다. That is why 가 is used.

• 비가 와요 = It rains / It’s raining
• 눈이 와요 = It snows / It’s snowing

You can use 비는 in some contexts, but it changes the nuance. 는 would make 비 the topic, often with contrast:

• 비는 오지만... = As for rain, it does fall, but...
• 비는 오면 안 돼요 = Rain, if it comes, is bad / It must not rain

For a plain conditional statement, 비가 오면 is the most natural.

This is just how the conditional form is made.

For verbs, attach -면 to the stem. The stem of 오다 is 오-, so:

• 오다 → 오면

A few more examples:

• 하다 → 하면
• 보다 → 보면
• 있다 → 있으면

So 비가 오면 literally means if rain comes, which is how Korean expresses if it rains.

타지 말고 means don’t ride it, and instead... or rather than riding it...

It is built like this:

• 타다 = to ride
• 타지 마 / 타지 마세요 = don’t ride
• 타지 말고 = don’t ride, and instead...

The ending -지 말고 is often used when telling someone:

1. Do not do X
2. Do Y instead

So in this sentence:

• 자전거를 타지 말고 = don’t ride a bicycle, and instead...
• 지하철을 타요 = take the subway

This makes the whole sentence sound like practical advice.

This is a very common question.

-지 말고

Used for commands, suggestions, or advice:

• 가지 말고 있어요. = Don’t go; stay.
• 커피 마시지 말고 물 마셔요. = Don’t drink coffee; drink water.

It often has the feeling of instead of X, do Y.

-지 않고

Means without doing X or not doing X and... It sounds more neutral and descriptive:

• 아침을 먹지 않고 학교에 갔어요. = I went to school without eating breakfast.
• 자전거를 타지 않고 지하철을 탔어요. = I took the subway instead of riding a bike.

So in your sentence, -지 말고 is used because the speaker is giving advice or instruction, not just describing events.

Because both are the direct objects of 타다.

In Korean, 타다 means to ride or to take for transportation, and the thing you ride takes 을/를:

• 자전거를 타다 = ride a bicycle
• 버스를 타다 = take a bus
• 지하철을 타다 = take the subway

So:

• 자전거를 타지 말고 = don’t ride a bicycle
• 지하철을 타요 = take the subway

This is different from English, where we might say go by subway. Korean normally uses 타다 with transportation.

타요 is polite, but it is not an honorific command form.

This sentence sounds like:

• general advice
• casual polite instruction
• a recommendation in conversation

So 지하철을 타요 here is like take the subway in a polite, conversational style.

If the speaker wants to sound more directly instructive or more respectful to the listener, they could say:

• 비가 오면 자전거를 타지 말고 지하철을 타세요.

That sounds more like:

• If it rains, don’t ride a bike; take the subway.

So:

• 타요 = polite statement/advice
• 타세요 = polite command/suggestion to the listener

It is most naturally understood as advice or a mild instruction.

Because of -지 말고 ... 타요, it sounds like the speaker is telling someone what they should do in that situation:

• If it rains, don’t ride a bicycle; take the subway.

It is not just neutral description. A purely descriptive sentence would look more like:

• 비가 오면 자전거를 타지 않고 지하철을 타요.
  • When it rains, I don’t ride a bike; I take the subway.

Your original sentence has more of a recommended action feeling.

It can mean either one, depending on context.

Korean -면 often covers both ideas:

• if it rains
• when it rains

In English, we separate these more clearly sometimes, but Korean often does not.

In this sentence, both are natural:

• If it rains, don’t ride a bike; take the subway.
• When it rains, don’t ride a bike; take the subway.

The exact interpretation depends on the situation.

Because Korean often omits subjects when they are obvious from context.

English usually needs a subject:

• If it rains, don’t ride a bicycle; take the subway.

In Korean, if the listener is clearly the person being advised, there is no need to say you.

So the sentence naturally leaves it out:

• 비가 오면 자전거를 타지 말고 지하철을 타요.

If you explicitly added you, it would usually sound unnatural or unnecessary in ordinary conversation.

Korean often uses the present form where English would use future meaning.

So 지하철을 타요 can mean:

• take the subway
• will take the subway
• should take the subway

The time is understood from context. Since 비가 오면 already sets up a future or repeated condition, the plain present-style form is enough.

This is very normal in Korean:

• 내일 가요. = I’m going tomorrow.
• 시간이 있으면 만나요. = If you have time, let’s meet / we’ll meet.

So there is nothing missing here.

Yes.

This sentence can describe:

1. general advice

   • If it rains, don’t ride a bike; take the subway.

2. a usual pattern

   • When it rains, don’t ride a bike; take the subway.

Korean often leaves that distinction to context. Without more context, it sounds like a general recommendation that could also apply repeatedly.

Yes, but the tone changes.

타요

Polite and conversational.

• common in everyday speech

탑니다

Formal and polite.

• common in announcements, presentations, formal writing, or careful speech

타세요

Polite suggestion/command.

• more directly addressed to the listener

So these versions are all possible, with slightly different tones:

• 비가 오면 자전거를 타지 말고 지하철을 타요.

  • conversational advice

• 비가 오면 자전거를 타지 말고 지하철을 탑니다.

  • more formal

• 비가 오면 자전거를 타지 말고 지하철을 타세요.

  • direct polite instruction

In casual speech, yes, Korean speakers often omit particles like 를 when the meaning is clear:

• 비가 오면 자전거 타지 말고 지하철 타요.

This sounds natural in conversation.

However, for learners, the full version is better because it clearly shows the grammar:

• 자전거를 타지 말고
• 지하철을 타요

Using the particles helps you see the sentence structure more clearly.

The sentence follows the normal Korean pattern: condition + object + verb + object + verb.

Broken down:

• 비가 오면 = if it rains
• 자전거를 타지 말고 = don’t ride a bicycle, and instead...
• 지하철을 타요 = take the subway

Korean puts verbs at the end of each clause, so the sentence may feel backward compared with English at first.

A very literal order would be:

• If rain comes, bicycle don’t ride, and subway ride.

That is why Korean learners often need time to get used to hearing the key action at the end.

Yes, it is very useful to memorize 비가 오다 as a set phrase.

Common weather expressions include:

• 비가 오다 = to rain
• 눈이 오다 = to snow
• 바람이 불다 = the wind blows
• 해가 뜨다 = the sun rises / comes out

So instead of thinking of 오다 only as to come, it helps to learn that with weather nouns it can form natural weather expressions:

• 비가 와요. = It’s raining.
• 비가 오면... = If/when it rains...