A professora fez-nos usar cola para fechar a capa, mas eu preferi um clip.

In European Portuguese, it is very normal to use the definite article before a noun like professora when you mean a specific person:

A professora = the teacher

English often leaves this out in some contexts, but Portuguese usually keeps it. So A professora fez-nos... sounds completely natural.

Because cola here is being used as an uncountable material noun, like glue in English.

So:

• usar cola = use glue
• comprar pão = buy bread
• beber água = drink water

If you said usar a cola, that would usually mean use the glue — a specific glue already known in the context.

This is the very common causative structure:

fazer + alguém + infinitive

It means to make someone do something or to have someone do something.

So here:

• fez = made
• nos = us
• usar = use

Together:

fez-nos usar = made us use

This structure is extremely useful in Portuguese:

• Ela fez-me esperar. = She made me wait.
• O professor fez-nos escrever. = The teacher made us write.

Because in European Portuguese, object pronouns are very often placed after the verb in affirmative main clauses. This is called enclisis.

So in Portugal, you commonly get:

• fez-nos
• disse-me
• deu-lhe

with a hyphen.

A Brazilian learner will often see:

• nos fez
• me disse

But for European Portuguese, fez-nos is the expected standard form here.

Because after causative fazer, the second verb normally stays in the infinitive.

So:

• A professora fez-nos usar cola.
• not A professora fez-nos usamos cola.

This is just how the pattern works:

fazer + object + infinitive

Other examples:

• Fez-me rir. = It made me laugh.
• Fez-nos estudar. = She made us study.

Nos is the object pronoun meaning us.

In this sentence, it refers to the people who were made to do the action of usar.

So the structure is:

• A professora = the teacher
• fez = made
• nos = us
• usar cola = use glue

Even though in English we say made us use, in Portuguese the pronoun sits with the first verb: fez-nos usar.

Para + infinitive is a very common way to express purpose in Portuguese.

So:

• para fechar a capa = to close / fasten the cover
• literally: for closing the cover

This is the normal way to say in order to...

Examples:

• Usei a tesoura para cortar o papel. = I used the scissors to cut the paper.
• Trouxe cola para arranjar isto. = I brought glue to fix this.

Yes, basically — but in context it can also mean something like fasten, seal, or close up.

Portuguese fechar has a broad range, just like English close can. With something like a capa, it depends on what kind of object we are talking about:

• a folder cover
• a notebook cover
• a protective cover
• something being sealed or fixed shut

So fechar a capa is natural Portuguese, even if the exact English wording might vary by context.

Capa usually means cover, not cape in this kind of sentence.

Depending on context, it could be:

• the cover of a notebook
• the cover of a folder
• the cover of a book
• an outer cover or protective layer

So a learner should think of capa as a very common word for cover.

That is true: Portuguese often leaves out subject pronouns because the verb ending already shows the person.

So preferi already means I preferred.

But eu is included here for contrast:

..., mas eu preferi um clip.
= ..., but I preferred a clip.

The eu adds emphasis, almost like but I in English.

Compare:

• Mas preferi um clip. = But I preferred a clip.
• Mas eu preferi um clip. = But I preferred a clip.

The second version sounds more contrastive.

Preferi is the pretérito perfeito: it describes a completed action or decision in the past.

So here it means something like: at that moment, I chose / preferred a clip.

Preferia is the imperfect, which would suggest:

• a habitual preference in the past
• background description
• or sometimes a more tentative/polite idea depending on context

In this sentence, preferi fits better because it sounds like a specific reaction to the situation.

Yes, clip is used in European Portuguese, especially for a paper clip or a similar small fastening item, depending on context.

It is treated as a masculine noun, so:

• um clip
• not uma clip

Like many borrowed words, its gender just has to be learned as part of the noun.

In practice, a Portuguese speaker would understand um clip very easily in this sentence.

Yes. Portuguese has several ways to express the same general idea, with slightly different nuances.

For example:

• A professora fez-nos usar cola...
  = The teacher made us use glue.
  Neutral causative structure.

• A professora obrigou-nos a usar cola...
  = The teacher forced us to use glue.
  Stronger idea of obligation.

• A professora mandou-nos usar cola...
  = The teacher told/ordered us to use glue.
  More about giving an instruction.

So fez-nos usar is natural, but it is not the only possible wording.