konya no uti ni mousikomisyo wo kaite, asita made ni dasu tumori desu.

今夜のうちに means before tonight is over or sometime tonight, while it is still tonight.

The pattern X のうちに often means:

• while X is still going on
• before X ends
• within X

So 今夜のうちに gives the nuance that the writing should be finished tonight, not later.

The の links 今夜 and うち into the set expression X のうちに.

So:

• 今夜 = tonight
• うち = inside / while / during
• 今夜のうちに = within tonight, before tonight is over

This is a common pattern:

• 今日のうちに = within today
• 今週のうちに = within this week
• 今年のうちに = within this year

So the の is not optional here.

Yes, it is the same basic word うち, but here it is being used in a grammar pattern, not in the everyday home/house sense.

In X のうちに, うち has the idea of within the limits of something or while something lasts.

So here it does not mean home. It means something like within the time span of tonight.

明日までに means by tomorrow or no later than tomorrow.

The key point is までに:

• まで = until / up to
• までに = by, before a deadline

So:

• 明日までに出す = submit it by tomorrow
• 明日まで出す would not fit here in the same way

A useful comparison:

• 5時まで勉強する = study until 5:00
• 5時までに行く = go there by 5:00

書いて is the て-form, and here it connects two actions:

1. 申込書を書く
2. 明日までに出す

So the sentence means something like:

• fill out the application form, and submit it by tomorrow

The て-form is very commonly used to link actions in Japanese. It often has the sense of and, and then, or after doing that.

Yes, slightly.

• 書いて、明日までに出す = write it and submit it by tomorrow
• 書いてから、明日までに出す = after writing it, submit it by tomorrow

Both are possible, but 書いて is a more neutral, natural link between the two actions.
書いてから would put extra emphasis on the order: first write it, then submit it.

Since the order is already obvious, 書いて is enough.

Literally, yes, but in natural English it often means fill out the application form.

Japanese 書く is often used for filling in documents, forms, and paperwork. So:

• 申込書を書く = fill out / write the application form

This is normal Japanese.

A useful contrast:

• 申込書を書く = fill out the application form
• 申込書に書く = write on the application form

So the particle changes the meaning.

It is read もうしこみしょ.

It is made from:

• 申込 = application / sign-up
• 書 = document, written form

So 申込書 means application form.

You may also see the verb 申し込む, which means to apply or to sign up.

In this sentence, 出す means submit, hand in, or send in.

The basic meaning of 出す is very broad: put out, take out, send, submit, and more.
With documents and forms, it often means:

• submit
• turn in
• hand in
• send in

So 申込書を出す is a very natural way to say submit the application form.

つもりです expresses intention or plan.

So 出すつもりです means:

• I intend to submit it
• I plan to submit it

It tells you what the speaker means to do, but it is not as strong as a guarantee or promise. It is about the speaker’s present intention.

A few related points:

• つもりです = polite
• つもりだ = plain / casual

Because before つもり, the verb normally appears in its plain form.

So:

• 出す
  • つもりです
• not 出しますつもりです

This is completely normal Japanese grammar.

Also, in longer sentences, Japanese often uses plain forms in non-final parts, while the final part carries the politeness. So the sentence is still polite overall because it ends with です.

Yes, the subject is omitted, which is very common in Japanese.

From context, the speaker is most likely talking about themself, so the natural subject is:

• I

That is especially likely because つもりです usually expresses the speaker’s own intention unless the context clearly says otherwise.

So even without 私は, the sentence naturally reads as I intend to...