Esta ficha é curta, mas a próxima avaliação vai ser mais difícil.

In European Portuguese, ficha often means a worksheet, exercise sheet, or school handout. In some contexts it can also mean a test sheet or work sheet, depending on what students are doing.

So in this sentence, ficha is probably not just a generic card or file. It most likely refers to a piece of schoolwork.

Because ficha is a feminine singular noun, and the demonstrative has to agree with it.

• esta = feminine singular
• este = masculine singular

Examples:

• esta ficha
• este livro

Agreement is very important in Portuguese.

For the same reason: curta agrees with ficha, which is feminine singular.

• ficha curta = feminine singular
• livro curto = masculine singular

So the adjective changes to match the noun:

• curto → masculine singular
• curta → feminine singular
• curtos → masculine plural
• curtas → feminine plural

Yes. Curta means short, but in this context it probably means not very long or not very extensive.

With schoolwork, uma ficha curta usually means:

• a short worksheet
• a brief exercise sheet
• something that does not take long to complete

It does not necessarily mean physically small.

Here a is the definite article meaning the.

So:

• a próxima avaliação = the next assessment

Portuguese uses definite articles more often than English does. In this sentence, using a sounds natural and standard.

Also, próxima agrees with avaliação, which is feminine singular:

• a próxima avaliação
• o próximo teste

Próxima means next, and avaliação means assessment, evaluation, or sometimes test, depending on the school context.

So a próxima avaliação could mean:

• the next assessment
• the next evaluation
• the next test

In natural English, the next test might sound more idiomatic in many school situations, even if the Portuguese word is avaliação.

They are related to schoolwork, but they are not the same thing.

• ficha often means a worksheet, exercise sheet, or practice sheet
• avaliação is something more formal used to assess performance, like an assessment or test

So the sentence contrasts:

• the current piece of work, which is short with
• the upcoming assessment, which will be harder

Vai ser is a very common way to form the future in Portuguese.

It is made with:

• ir in the present tense + infinitive

So:

• vai ser = is going to be / will be

Here:

• vai = he/she/it goes
• ser = to be

Together, vai ser means will be.

This is extremely common in spoken Portuguese and sounds very natural.

Yes, absolutely.

• vai ser mais difícil
• será mais difícil

Both mean will be more difficult.

The difference is mainly one of style and register:

• vai ser is very common in everyday speech
• será is a simple future form and can sound a bit more formal, more written, or sometimes more direct

In conversation, vai ser is often the more natural choice.

Portuguese usually forms the comparative with:

• mais
  • adjective

So:

• mais difícil = more difficult
• mais curto = shorter / more short
• mais fácil = easier / more easy

Unlike English, Portuguese does not usually add a special ending like -er to most adjectives.

So the pattern is very simple:

• mais + adjective = more + adjective

Because not all Portuguese adjectives have different masculine and feminine forms.

Some adjectives change:

• curto / curta

But some have the same form for both masculine and feminine in the singular:

• difícil
• fácil
• grande

So you get:

• o teste é difícil
• a avaliação é difícil

The adjective stays the same.

Only the plural changes:

• difíceis

Mas means but.

It connects two contrasting ideas:

• Esta ficha é curta
• a próxima avaliação vai ser mais difícil

So the sentence is saying: this current task is short, but the next assessment will be harder.

It is a very common conjunction in Portuguese.

The accent in é is important because it distinguishes it from e.

• é = is
• e = and

So:

• é curta = is short
• e curta would be wrong here

This accent is not optional; it changes the word.

They mainly show stress and sometimes help distinguish pronunciation.

• próxima: the stress falls on pró
• avaliação: the stress falls on the final ção
• difícil: the stress falls on fí

For learners, the most useful thing is to remember that written accents in Portuguese usually tell you where the word is stressed.

Because after ser, Portuguese normally places the adjective in the same way English does:

• A ficha é curta
• A avaliação é difícil

This is a very standard structure:

• noun + ser + adjective

So there is nothing unusual about the word order here.

Yes, it sounds natural.

A European Portuguese speaker could very naturally say:

• Esta ficha é curta, mas a próxima avaliação vai ser mais difícil.

It is a normal, everyday sentence, especially in a school context. The vocabulary and grammar are standard and idiomatic.