O aluno inteligente fez um molde.

In Portuguese, singular countable nouns usually need an article or another determiner when you are talking about a specific person or thing.

So:

• o aluno = the student
• um aluno = a student

Saying just aluno on its own would usually sound incomplete in a normal sentence like this.

Because aluno is a masculine noun.

In Portuguese, nouns have grammatical gender, and the article must match:

• o aluno = the male student / the student
• a aluna = the female student

So even though English uses just the student, Portuguese requires you to choose the correct gendered form.

Aluno is the masculine form, and aluna is the feminine form.

So:

• o aluno inteligente = the intelligent male student / the intelligent student
• a aluna inteligente = the intelligent female student

Notice that inteligente stays the same in both masculine and feminine singular. That is very common with adjectives ending in -e.

In Portuguese, adjectives often come after the noun, unlike in English.

So:

• o aluno inteligente literally follows the pattern the student intelligent

This is the most natural order here.

You can sometimes move adjectives before the noun in Portuguese, but that often changes the tone or emphasis. For a straightforward description, o aluno inteligente is the normal choice.

Because inteligente is an adjective with the same form for masculine and feminine singular.

Compare:

• o aluno inteligente
• a aluna inteligente

Only the article and noun change. The adjective stays the same.

In the plural, it becomes:

• os alunos inteligentes
• as alunas inteligentes

So the singular form is inteligente, and the plural form is inteligentes.

Fez is the preterite form of the verb fazer (to do / to make).

Here it means a completed action in the past:

• fez = made / did

So the sentence describes something the student completed.

Examples:

• Hoje faz um molde. = Today he/she makes a mold.
• Ontem fez um molde. = Yesterday he/she made a mold.

It comes from fazer, which is an irregular verb.

Some common forms are:

• eu faço = I do / I make
• tu fazes = you do / you make
• ele/ela faz = he/she does / makes
• nós fazemos = we do / make
• eles/elas fazem = they do / make

Preterite:

• eu fiz = I did / made
• tu fizeste
• ele/ela fez
• nós fizemos
• eles/elas fizeram

So fez is the he/she/you-formal preterite of fazer.

Because molde is a masculine noun.

In Portuguese, noun gender is not always predictable from the ending. Even though molde ends in -e, it is masculine:

• um molde = a mold
• o molde = the mold

This is something learners often need to memorize noun by noun.

Its plural is:

• os moldes = the molds

Molde can mean several related things depending on context, such as:

• mold
• template
• pattern
• cast

So in different situations it could refer to something used in:

• crafts
• sewing
• manufacturing
• art
• construction

Even if the meaning has already been given to you, it is useful to know that molde is a fairly flexible word and does not always refer to just one exact object.

Yes. That would also be correct, but the meaning changes slightly.

• O aluno inteligente fez um molde. = The intelligent student made a mold.
• Um aluno inteligente fez um molde. = An intelligent student made a mold.

So the difference is the same basic one as the versus a/an in English.

In European Portuguese, fez is pronounced roughly like fezh or fesh, depending on the speaker and region.

A useful approximation is:

• fez ≈ fesh

That final z often sounds like sh in European Portuguese when it comes at the end of a word.

So the full sentence sounds approximately like:

• O aluno inteligente fez um molde
• roughly: u ah-LOO-noh in-teh-li-ZHEN-tuh fesh oom MOL-duh

This is only an approximation for English speakers, but it helps you notice some typical European Portuguese pronunciation patterns.

Yes, Portuguese often allows the subject to be omitted if it is understood from context.

So:

• Fez um molde. = He/She made a mold.

However, in your full sentence, o aluno inteligente is included because the speaker wants to identify exactly who did it.

Portuguese does this a lot because the verb form often gives information about the subject. In this case, fez could mean he/she/you-formal did, so context is still important.

The normal order is:

• O aluno = subject
• inteligente = adjective describing the subject
• fez = verb
• um molde = direct object

So the basic structure is:

Subject + Verb + Object

More precisely, inside the subject phrase you get:

Article + Noun + Adjective

That makes the whole sentence very typical and natural Portuguese word order.