siheom jeone neomu geokjeonghaji ma.

시험 전에 means before the exam.

It is made of:

• 시험 = exam, test
• 전 = before
• 에 = a particle that appears in this time expression

So N 전에 is a very common pattern meaning before N.

Examples:

• 수업 전에 = before class
• 식사 전에 = before the meal
• 자기 전에 = before sleeping

In this sentence, 시험 전에 sets the time: before the exam.

Yes, it is historically the same particle, but for learners the easiest way is to treat N 전에 as a fixed expression meaning before N.

You do not usually need to think of it as separately translating to at or in here. The whole chunk 시험 전에 simply means before the exam.

Also, in everyday Korean, 시험 전 and 시험 전에 can both appear, but 시험 전에 is very standard and natural when introducing what happens before something.

Here, 너무 means something like too much or overly.

So 너무 걱정하지 마 means:

• don’t worry too much
• don’t worry so much

This is a useful point because 너무 can sometimes feel like very in casual modern Korean, but in this sentence the more natural English idea is too much / so much.

It comes from the verb 걱정하다, which means to worry.

Breakdown:

• 걱정하다 = to worry
• 걱정하지 = do not worry / worrying not...
  This is the verb stem with negation connection: -하지
• 마 = don’t

So 걱정하지 마 literally works like don’t worry.

A very useful grammar pattern is:

• Verb-지 마 = don’t do ...

Examples:

• 가지 마 = don’t go
• 먹지 마 = don’t eat
• 울지 마 = don’t cry

So:

• 걱정하지 마 = don’t worry

마 is a casual, informal way to say don’t ....

So 걱정하지 마 sounds like something you would say to:

• a friend
• a younger person
• someone you are close to

If you want to say it politely, you would usually say:

• 시험 전에 너무 걱정하지 마세요.

That means the same thing, but in a polite style.

So the difference is mainly speech level, not meaning.

Grammatically, yes, it uses the negative imperative form, so it is a kind of command: don’t worry.

But in real use, it often feels softer than an English command. It is commonly used as:

• reassurance
• comfort
• advice
• encouragement

So 시험 전에 너무 걱정하지 마 usually sounds like:

• Try not to worry too much before the exam rather than a harsh order.

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

In 시험 전에 너무 걱정하지 마, the unstated subject is usually you:

• Don’t worry too much before the exam

Korean does this very often. If the listener is clear, there is no need to say 너는.

In fact, adding 너는 can sound unnecessary or even too direct in many situations.

That is exactly what it is.

• 걱정 = worry, चिंता-like noun idea
• 하다 = to do

So 걱정하다 literally means something like to do worrying, which becomes to worry in natural English.

This pattern is extremely common in Korean:

• 공부하다 = to study
• 운동하다 = to exercise
• 준비하다 = to prepare
• 걱정하다 = to worry

Because of this, when you conjugate it, you treat it like a 하다 verb:

• 걱정해
• 걱정했어
• 걱정하지 마

In Korean, adverbs usually come before the verb or verb phrase they modify.

So:

• 너무 걱정하지 마 = don’t worry too much

This is the normal word order.

Korean is generally Subject-Object-Verb, and adverbs often appear before the verb:

• 빨리 가 = go quickly
• 조용히 말해 = speak quietly
• 너무 걱정하지 마 = don’t worry too much

Yes, that is possible, and the meaning is very similar.

However, 걱정하다 is most directly to worry, so Don’t worry too much before the exam is the most literal and natural match.

Don’t be too worried before the exam is also understandable, but it sounds a little more like describing a state, while the Korean verb 걱정하다 is usually better matched by the action/state verb worry.

Yes. That would mean simply:

• Don’t worry before the exam

Adding 너무 makes it softer and more natural in many situations, because people often do worry before exams. So instead of saying don’t worry at all, the speaker is saying:

• don’t worry too much
• don’t overdo the worrying

That often sounds more realistic and comforting.

시험 전에는 adds the topic particle 는.

So:

• 시험 전에 너무 걱정하지 마 = Don’t worry too much before the exam.
• 시험 전에는 너무 걱정하지 마 = As for before the exam, don’t worry too much.

The version with 는 gives a little extra emphasis or contrast. It can suggest something like:

• at least before the exam, don’t worry too much
• before the exam in particular, don’t worry too much

The sentence you gave, without 는, is simpler and very natural.

시험 can mean both exam and test, depending on context.

So 시험 전에 너무 걱정하지 마 could be understood as:

• Don’t worry too much before the exam.
• Don’t worry too much before the test.

If the context is school, either may be possible. English choice depends on what kind of assessment it is.