O professor fez-nos carregar na tecla Enter antes de enviar o formulário.

In Portuguese, professor is often broader than English professor. It commonly means teacher, including a school teacher, not only a university professor.

So in many contexts:

• o professor = the teacher
• a professora = the teacher (female)

English speakers often notice this because professor is a narrower word in English than professor in Portuguese.

Fez-nos is made up of:

• fez = made / caused / had (past tense of fazer)
• nos = us

So fez-nos carregar means made us press or had us press.

This is a very common Portuguese structure:

• fazer + someone + infinitive

Examples:

• Fez-me esperar. = He/She made me wait.
• Fez-nos entrar. = He/She made us go in.

In standard European Portuguese, unstressed object pronouns like me, te, se, nos, vos, o, a, os, as, lhe, lhes often come after the verb in a normal affirmative main clause. This is called enclisis.

So in Portugal, fez-nos is the normal pattern.

Compare:

• O professor fez-nos carregar... = standard European Portuguese
• O professor nos fez carregar... = much more Brazilian in feel

The hyphen is required when the pronoun is attached after the verb.

Also, some words force the pronoun to come before the verb. For example:

• O professor não nos fez carregar...

Here não attracts the pronoun, so you get nos fez, not fez-nos.

Because fazer in this causative meaning is followed by a bare infinitive.

So Portuguese says:

• fazer alguém fazer alguma coisa
• literally: make someone do something

That is why you get:

• fez-nos carregar

and not:

• fez-nos a carregar

This is similar to English make someone do something, not make someone to do something.

Compare with another verb:

• obrigou-nos a carregar na tecla Enter

Here obrigar does take a before the infinitive, but fazer does not.

Because after causative fazer, Portuguese normally uses the infinitive.

So:

• O professor fez-nos carregar...

not:

• O professor fez-nos carregámos...
• O professor fez-nos carregarmos... in this structure

The idea is the same as in English:

• He made us press not
• He made us we pressed

So carregar stays in the infinitive because it is part of the make/have someone do something pattern.

In European Portuguese, carregar em or carregar na is a common way to say press when talking about buttons, keys, and similar controls.

Here:

• na = em + a
• tecla is feminine singular
• so em a tecla contracts to na tecla

So:

• carregar na tecla Enter = press the Enter key

This is very natural in Portugal.

You may also hear:

• carregar no botão = press the button
• carregar nas teclas = press the keys

Yes. All of these can be used, but they differ a bit in style and frequency.

Common possibilities:

• carregar na tecla Enter — very natural in European Portuguese, especially in everyday speech
• pressionar a tecla Enter — also clear and natural, slightly more neutral/international
• premir a tecla Enter — correct, but often sounds more formal, technical, or instructional

So the original sentence sounds perfectly natural for Portugal.

Because after the preposition antes de, Portuguese uses the infinitive, not a finite verb.

So:

• antes de enviar o formulário = before sending the form

Not:

• antes de enviou
• antes de envia

This pattern is extremely common:

• antes de sair = before leaving
• depois de comer = after eating
• sem dizer nada = without saying anything

It is understood from context, but this is a good question because the sentence can feel a little open without more marking.

In practice, the most likely meaning is that we/us are the ones sending the form:

• The professor made us press Enter before sending the form.

Portuguese often leaves the subject of an infinitive unstated when it is clear enough from context.

If you want to make us explicit, you can use the personal infinitive:

• antes de enviarmos o formulário

That removes ambiguity more clearly.

So:

• antes de enviar o formulário = before sending the form
• antes de enviarmos o formulário = before we sent / before we were to send the form

Portuguese uses definite articles more often than English does.

So o formulário is very natural even where English might sometimes just say the form or where learners might expect no article.

Here it refers to a specific form already understood in the situation, so the article sounds completely normal:

• enviar o formulário

Portuguese often likes the article with concrete, identifiable things in context.

Fez is the pretérito perfeito: it presents the action as a completed event.

So the sentence sounds like a specific finished action in the past:

• The teacher made us press Enter before sending the form.

If you said fazia-nos, that would usually suggest something more habitual, repeated, or descriptive:

• O professor fazia-nos carregar na tecla Enter... = The teacher used to make us press the Enter key...

So:

• fez-nos = one completed past event
• fazia-nos = repeated or ongoing past habit/background situation