asita ha hayai kara, sitizi ni okosite kudasai.

は marks 明日 as the topic: as for tomorrow.

So 明日は gives a feeling like:

• As for tomorrow, ...
• Tomorrow, ...

It sets the time frame for the whole sentence. In English we often just say tomorrow without a special marker, but Japanese often uses は to highlight what the sentence is about.

Without は, 明日七時に起こしてください is still understandable, but 明日は sounds more natural when the speaker is setting up tomorrow as the topic.

Yes, 早い can mean early, and that is the meaning here.

Japanese has two similar words:

• 早い = early
• 速い = fast

In this sentence, 早い means something like:

• tomorrow is an early day
• I have an early start tomorrow
• I need to get up early tomorrow

Japanese often leaves out words that are understood from context, so 明日は早い is a natural shorthand. It does not mean tomorrow itself is fast.

Because 早い is acting as a complete predicate here: it’s early / I have an early start.

• 早い = an -i adjective
• 早く = the adverb form, used when modifying a verb

For example:

• 明日は早い。 = Tomorrow is early / I have to be up early tomorrow.
• 明日早く起きます。 = I will get up early tomorrow.

So in your sentence, the speaker is giving a reason: Because tomorrow is early...

から means because here.

The first part gives the reason:

• 明日は早いから = because tomorrow is an early day / because I have to be up early tomorrow

Then comes the request:

• 七時に起こしてください = please wake me up at seven

So the whole structure is:

• reason + から, request

This is very common in Japanese.

に marks a specific point in time.

• 七時に = at seven o’clock

You use に with a precise time like:

• 六時に = at 6:00
• 月曜日に = on Monday
• 三月一日に = on March 1st

So 七時に起こしてください means please wake me up at seven.

This is a very important difference:

• 起きる = to wake up / get up oneself
• 起こす = to wake someone else up

So:

• 起きてください = Please get up.
• 起こしてください = Please wake me up / wake someone up.

In your sentence, the speaker is asking another person to do the waking, so 起こす is the correct verb.

Japanese often leaves out pronouns when they are obvious from context.

So 七時に起こしてください literally just says:

• Please wake up [someone] at seven

But in a normal situation, it is clearly understood to mean:

• Please wake me up at seven

If you wanted to say it explicitly, you could say:

• 七時に私を起こしてください。

But that usually sounds less natural unless you need emphasis or contrast.

It is built like this:

• 起こす = dictionary form, to wake someone up
• 起こして = te-form
• ください = please do ...

So:

• 起こして + ください = please wake [someone] up

This is one of the most basic and common polite request patterns in Japanese:

• 見てください = please look
• 待ってください = please wait
• 教えてください = please tell me

In normal writing, this is usually written as 起こしてください without a space.

Yes, it is polite and normal.

The politeness comes from ください, which makes the request courteous:

• 起こして = wake me up / wake me up, okay?
• 起こしてください = please wake me up

It is not super formal, but it is definitely polite enough for many everyday situations.

If you wanted to be even more polite, you could say something like:

• 七時に起こしていただけますか。 = Could you wake me up at seven?

The comma separates the reason from the main request:

• 明日は早いから、七時に起こしてください。

It helps readability, especially in longer sentences.

Japanese commas are often more flexible than English commas, so this comma is helpful and natural, but punctuation in Japanese is not always as strict as in English.

In this sentence:

• 明日 is read あした
• 七時 is read しちじ

A common point of confusion is 七, because it can be read different ways in different words. For time, 七時 is normally しちじ, not ななじ.

So the full sentence is read:

• あした は はやい から、しちじ に おこして ください。

No. Standard Japanese normally does not use spaces between words.

This sentence would usually be written as:

• 明日は早いから、七時に起こしてください。

The spaces are often added in textbooks or beginner materials to make the structure easier to see.

So they are useful for learning, but not normal in everyday Japanese writing.