Тебе лучше бы лечь спать пораньше, потому что завтра утром экзамен.

Because Russian uses the dative case after expressions like кому-то лучше... = it is better for someone to...

So:

• ты = you as the subject
• тебе = to/for you

In this sentence, тебе лучше... literally means something like:

• For you, it would be better to...

This is a very common Russian pattern for giving advice:

• Мне нужно идти. = I need to go.
• Тебе пора спать. = It’s time for you to sleep.
• Ему лучше отдохнуть. = He’d better rest.

So тебе is there because Russian frames this idea as “to you / for you, it is better...”

Лучше бы here means something like:

• you’d better
• it would be better if...

So:

• Тебе лучше бы лечь спать пораньше = You’d better go to bed earlier

A useful point: лучше бы often adds a shade of:

• advice
• warning
• mild insistence
• sometimes even slight criticism, depending on tone

Compare:

• Тебе лучше лечь спать пораньше. = It’s better for you to go to bed earlier.
• Тебе лучше бы лечь спать пораньше. = You’d better go to bed earlier.

The version with бы can sound a bit more like the speaker is urging the person.

Бы is a particle often connected with:

• conditional meaning
• hypothetical meaning
• softened recommendation
• wishes/regret in other contexts

In this sentence, it helps create the sense of “would be better” rather than just “is better.”

So:

• лучше = better
• лучше бы = would be better / had better

You will also see бы in many other structures, for example:

• Я бы пошёл. = I would go.
• Лучше бы ты пришёл раньше. = You should have come earlier / It would have been better if you had come earlier.

So here бы adds a more conditional/recommending tone.

This is about aspect.

• лечь = perfective
• ложиться = imperfective

Both can mean to go to bed / lie down, but they are used differently.

лечь

Perfective means a single completed action.
Here the speaker means one specific action:

• go to bed earlier tonight

So лечь fits very naturally.

ложиться

Imperfective would suggest:

• a process
• a repeated/habitual action
• a general rule

For example:

• Тебе лучше ложиться спать пораньше.
  = You’d better go to bed earlier in general / as a habit.

So:

• лечь спать = go to bed this time
• ложиться спать = go to bed regularly / be in the habit of going to bed

Лечь спать is a very common Russian expression meaning:

• to go to bed
• literally: to lie down to sleep

It combines:

• лечь = to lie down
• спать = to sleep

Russian often uses this kind of structure where English uses one simple phrase.

Very common examples:

• идти спать = to go to sleep / go to bed
• лечь спать = to lie down and go to sleep
• пойти гулять = to go for a walk
• сесть поесть = to sit down to eat

So лечь спать should be learned as a set phrase.

Пораньше means:

• a bit earlier
• somewhat earlier
• earlier than usual / earlier than now planned

It comes from раньше = earlier, with the prefix по-, which often makes the meaning softer or more moderate.

Compare:

• раньше = earlier
• пораньше = a little earlier / fairly early / earlier than usual

So:

• лечь спать раньше = go to bed earlier
• лечь спать пораньше = go to bed a bit earlier

In this sentence, пораньше sounds natural because it’s practical advice, not an extreme command.

Because Russian often uses time expressions in the instrumental case without a preposition to mean in the morning / in the evening / at night, etc.

Here:

• утро = morning
• утром = in the morning

So:

• завтра утром = tomorrow morning

This is just a standard time expression.

Other examples:

• сегодня вечером = this evening
• ночью = at night
• днём = during the day

So завтра утром is a fixed, natural way to say tomorrow morning.

Russian often omits the verb to be in the present tense.

So:

• завтра утром экзамен literally looks like tomorrow morning exam
• but it means there is an exam tomorrow morning or the exam is tomorrow morning

Russian does this all the time in present-tense sentences:

• Он дома. = He is at home.
• Я студент. = I am a student.
• Сегодня урок. = There is a lesson today.

Even though завтра refers to the future, Russian can still use this kind of verbless sentence when stating a scheduled event, especially in everyday speech.

You could also hear:

• Завтра утром будет экзамен. = There will be an exam tomorrow morning.
• У тебя завтра утром экзамен. = You have an exam tomorrow morning.

But the version in your sentence is shorter and very natural.

Because экзамен is the main noun in a sentence that basically means:

• There is an exam tomorrow morning
• The exam is tomorrow morning

In Russian, when the sentence is built this way, the noun is often in the nominative:

• Сегодня встреча. = There’s a meeting today.
• Завтра урок. = There’s a lesson tomorrow.
• Утром экзамен. = There’s an exam in the morning.

So экзамен is nominative because it functions like the core subject/predicate noun of the statement.

Yes. That version is also correct and natural.

• Тебе лучше лечь спать пораньше.
• Тебе лучше бы лечь спать пораньше.

Both mean roughly You’d better go to bed earlier.

The difference is nuance:

• лучше = straightforward advice
• лучше бы = slightly more emphatic, cautionary, or insistent

In real speech, the exact feeling depends a lot on intonation and context.

The sentence order is natural, but Russian word order is more flexible than English.

Your sentence:

• Тебе лучше бы лечь спать пораньше, потому что завтра утром экзамен.

This sounds normal because it presents:

1. the advice
2. then the reason

You could also hear variations like:

• Потому что завтра утром экзамен, тебе лучше бы лечь спать пораньше.
• Тебе лучше бы пораньше лечь спать, потому что завтра утром экзамен.

These are all understandable, but the original version is smooth and idiomatic.

Russian word order often changes for:

• emphasis
• rhythm
• what is already known vs. new information

So the order matters for style and focus, but not as rigidly as in English.

It sounds neutral conversational.

It is natural in everyday speech between:

• family members
• friends
• classmates
• anyone giving ordinary advice

It is not especially formal, but it is not slang either.

For a more formal or written style, someone might say:

• Тебе лучше лечь спать пораньше, потому что завтра утром у тебя экзамен.
• Тебе следует лечь спать пораньше... = You should go to bed earlier...

But your sentence itself is perfectly normal spoken Russian.

It could. In fact, that would also be very common:

• ...потому что у тебя завтра утром экзамен.

That version makes it explicit that the exam belongs to you: you have an exam tomorrow morning.

Without у тебя, the sentence still works because the meaning is obvious from context. If someone is telling you to go to bed earlier, the reason is clearly that you have an exam.

So:

• потому что завтра утром экзамен = because there’s an exam tomorrow morning
• потому что у тебя завтра утром экзамен = because you have an exam tomorrow morning

The second is more explicit; the first is a little more compact.

Yes, very often.

This is important because learners frequently meet лучше бы in sentences like:

• Лучше бы я остался дома. = I should have stayed home.
• Лучше бы ты молчал. = You should have kept quiet / You’d have been better off staying quiet.

In those cases, лучше бы expresses:

• regret
• criticism
• “it would have been better if...”

In your sentence, though, it is not about the past. It is about advice for the near future, so it means something like you’d better.

So the same phrase can have different shades depending on context:

• past/unrealized situation → regret or criticism
• future action → advice or warning