Я уезжаю завтра. Не может быть! Серьёзно, что ли?

Russian often uses the present tense for a planned or scheduled future action, especially when there is a clear time word like завтра.

So Я уезжаю завтра works like English I’m leaving tomorrow.

This usually suggests that the departure is already arranged or expected. If you wanted a simple future fact instead, you could also say Я уеду завтра.

• Я уезжаю завтра = I’m leaving tomorrow, already planned
• Я уеду завтра = I will leave tomorrow

Both are correct, but the nuance is a little different.

Уезжать / уехать means to leave, to depart, usually by some kind of transport and usually away from the place where the speaker is now.

Ехать just means to go / be going by vehicle.

So:

• Я еду завтра = I’m going tomorrow
• Я уезжаю завтра = I’m leaving tomorrow

The verb уезжать focuses on departure from a place, not just movement.

Yes. Russian often drops subject pronouns when the meaning is clear from the verb form.

So Уезжаю завтра is completely natural in conversation.

Including я can give a little extra emphasis or clarity:

• Уезжаю завтра = Leaving tomorrow
• Я уезжаю завтра = I’m leaving tomorrow

In this sentence, я is not required, but it is perfectly normal.

Because завтра is an adverb meaning tomorrow. It does not need a preposition.

This is similar to English:

• today
• tomorrow
• yesterday

You simply say:

• Я уезжаю завтра
• Он придёт сегодня
• Мы виделись вчера

Literally, Не может быть! means It cannot be!

But in real usage, it is a very common expression of surprise, disbelief, or shock. Depending on tone, it can mean things like:

• No way!
• That can’t be!
• You’re kidding!

It is often used as a complete exclamation, just like here.

This is an impersonal expression. Russian often uses third-person singular neuter-style verb forms in sentences where English uses it.

So Не может быть is basically:

• It cannot be
• That can’t be

Russian does not need to say the equivalent of it here. The expression is fixed and very common.

Yes, серьёзно is formally an adverb meaning seriously. But in conversation it is very often used by itself as a reaction, just like English Seriously?

So here it functions more like a conversational response than like part of a full sentence.

You can think of it as:

• Seriously?
• Really?

The exact feeling depends on intonation.

Что ли is a colloquial particle. It often adds uncertainty, mild disbelief, or a kind of or what? / really? feeling.

In Серьёзно, что ли?, it makes the reaction sound more conversational and slightly skeptical.

Possible natural English equivalents are:

• Seriously?
• Seriously, or what?
• For real?
• Really?

It does not translate word-for-word very neatly. It is better to learn it as a conversational particle.

No. Что ли is conversational and informal.

It is very common in speech and in informal writing, but you would usually avoid it in formal situations.

More neutral alternatives might be:

• Серьёзно?
• Правда?
• Неужели?

So Серьёзно, что ли? sounds casual and natural in everyday speech.

No, Russian word order is flexible.

You could also say:

• Я завтра уезжаю
• Завтра я уезжаю
• Уезжаю завтра

The basic meaning stays the same, but the emphasis changes a little:

• Я уезжаю завтра = neutral
• Я завтра уезжаю = slight emphasis on tomorrow
• Завтра я уезжаю = stronger focus on tomorrow
• Уезжаю завтра = natural if the subject is already clear

Russian word order often depends on what you want to highlight.

The comma helps separate серьёзно as a reaction word from что ли, which comments on the whole idea.

In informal writing, punctuation around expressions like this can vary a bit, because they reflect spoken language. But Серьёзно, что ли? is a normal written way to show the pause and intonation.

It sounds like:

• Seriously... really?
• Seriously, or what?

So the comma mainly helps show the conversational pause.