Eu deixo a mochila pronta à noite, para não esquecer o caderno de manhã.

Eu is optional in this sentence.

Portuguese often drops subject pronouns because the verb ending already shows who is doing the action. Deixo clearly means I leave / I get ready.

So both are natural:

• Eu deixo a mochila pronta à noite...
• Deixo a mochila pronta à noite...

Keeping eu can add a little emphasis, contrast, or clarity.

Because this sentence describes a habit or routine.

In Portuguese, the simple present often expresses things you do regularly:

• Eu deixo a mochila pronta à noite = I leave/get my backpack ready at night

Using estou deixando would usually suggest something happening right now, in progress:

• Estou deixando a mochila pronta agora = I’m getting the backpack ready now

So deixo is the natural choice for a repeated action.

This is a very common structure in Portuguese:

deixar + object + adjective

It means to leave something in a certain state.

So:

• deixar a mochila pronta = to leave the backpack ready
• in natural English, this often means to get the backpack ready or to pack it ahead of time

Similar examples:

• deixar a porta aberta = leave the door open
• deixar tudo organizado = leave everything organized

Because pronta agrees with mochila, which is a feminine singular noun.

• a mochila → feminine singular
• so the adjective must also be feminine singular: pronta

Compare:

• o caderno pronto = the notebook ready
• a mochila pronta = the backpack ready
• as mochilas prontas = the backpacks ready

Adjectives in Portuguese usually match the noun in gender and number.

Portuguese uses definite articles more often than English.

Here, a mochila and o caderno refer to specific, known things: the speaker’s backpack and notebook. In Portuguese, that often calls for the article.

So even where English might sound natural without an article in some contexts, Portuguese may still prefer one.

This is very normal:

• Vou pegar o celular.
• Ela esqueceu a chave.
• Preciso levar o caderno.

These are just fixed time expressions in Portuguese, and they do not all use the same preposition.

Common patterns are:

• de manhã = in the morning
• de tarde = in the afternoon
• à noite = at night / in the evening

So this is something you mostly learn as a chunk, not by strict logic.

A native speaker naturally says:

• de manhã
• de tarde
• à noite

not usually à manhã or de noite in this basic everyday pattern.

À is the contraction of:

• a
  • a = à

This is called crase in Portuguese.

In expressions like à noite, the grave accent shows that two a sounds have come together.

It is different from plain a:

• a mochila = the backpack
• à noite = at night / in the evening

For a learner, the most useful thing is to recognize à noite as a fixed expression.

Para introduces purpose:

• para não esquecer = so as not to forget / in order not to forget

In Portuguese, não normally comes before the verb it negates. Here it negates the infinitive esquecer:

• não esquecer = not to forget

So:

• para não esquecer o caderno = so I don’t forget the notebook

This word order is standard and very common.

Because esquecer can be used as a direct transitive verb:

• esquecer algo = forget something

So:

• esquecer o caderno = forget the notebook

This is very normal and standard.

You may also hear esquecer de in other situations, especially with another verb:

• esquecer de trazer o caderno = forget to bring the notebook

In everyday Brazilian speech, people may also say things like esqueci do caderno, but in your sentence, esquecer o caderno is straightforward and standard.

Not always. It is often a style or rhythm choice.

Both can be acceptable:

• Eu deixo a mochila pronta à noite, para não esquecer o caderno de manhã.
• Eu deixo a mochila pronta à noite para não esquecer o caderno de manhã.

The comma creates a small pause and makes the purpose phrase feel a little more separated. In a short sentence like this, many writers would omit it, but including it is not strange.

Yes. In Brazilian Portuguese, pra is extremely common in speech and informal writing.

So you will often hear:

• Eu deixo a mochila pronta à noite pra não esquecer o caderno de manhã.

That sounds natural and conversational.

Use para in more neutral or careful writing; use pra in informal spoken Brazilian Portuguese.

Because de manhã is a fixed expression meaning in the morning or in the mornings.

It does not normally use the article in this common time-expression sense.

So:

• de manhã = in the morning
• de tarde = in the afternoon
• à noite = at night / in the evening

If you say da manhã, that usually happens in a different structure, such as:

• às 7 da manhã = at 7 in the morning

So de manhã by itself is the normal form in your sentence.