O professor vai explicar a última lição aos alunos amanhã.

Not necessarily. In Brazilian Portuguese, professor/professora is the normal everyday word for teacher in general, not only a university professor.

So O professor could refer to:

• a schoolteacher
• a college instructor
• a professor in the English sense

You need context to know which one is meant.

Vai explicar uses a very common Brazilian Portuguese future pattern:

• ir in the present tense + infinitive

Here:

• vai = goes / is going
• explicar = to explain

Together, vai explicar means is going to explain or simply will explain.

A one-word future such as explicará is also correct, but it sounds more formal and is less common in everyday speech.

Because the subject is singular:

• O professor = one teacher

So the verb ir must also be singular:

• o professor vai

If the subject were plural, you would use vão:

• Os professores vão explicar...

Portuguese uses definite articles more often than English does.

In this sentence:

• o professor = the teacher
• a última lição = the last lesson
• aos alunos = to the students

Even when English might sometimes sound natural without the, Portuguese often keeps the article. This is very normal.

Also, aos already contains the article os:

• a + os = aos

Aos is a contraction of:

• a = to
• os = the for masculine plural nouns

So:

• a + os alunos becomes aos alunos

It is used because explicar commonly follows this pattern:

• explicar algo a alguém = to explain something to someone

In the sentence:

• a última lição = the thing being explained
• aos alunos = the people receiving the explanation

Sometimes you may hear explicar para os alunos, especially in informal speech, and people will understand it. But the most standard and expected structure is:

• explicar algo a alguém

So for learners, aos alunos is the safest and most idiomatic choice here.

Because adjectives in Portuguese usually agree with the noun in gender and number.

Here:

• lição is feminine singular
• so the adjective must also be feminine singular: última

Compare:

• o último livro = masculine singular
• a última lição = feminine singular
• os últimos livros = masculine plural
• as últimas lições = feminine plural

Adjectives often do come after the noun in Portuguese, but not always. Some adjectives commonly appear before the noun, and último is very natural before the noun when it means last or final.

So:

• a última lição sounds normal and natural

Putting it after the noun here would sound unusual or more literary:

• a lição última

So this is a good example of a common exception to the usual noun + adjective pattern.

Not necessarily. In Portuguese, the masculine plural can refer to:

• a group of males
• a mixed group of males and females

So aos alunos could mean:

• to the male students
• to the students in general, if the group is mixed

If the group were all female, you would normally say:

• às alunas

Yes, it can move. Amanhã is an adverb of time, and Portuguese allows some flexibility with its position.

These are all possible:

• O professor vai explicar a última lição aos alunos amanhã.
• Amanhã, o professor vai explicar a última lição aos alunos.
• O professor amanhã vai explicar a última lição aos alunos.

The version with amanhã at the end is very natural and neutral. Putting it first often gives it a little more emphasis.

They matter a lot.

• última: the accent shows the stress is on the first syllable: UL-ti-ma
• lição: the ç makes an s sound, so it sounds like lee-SOWN approximately, with a nasal ending
• amanhã: the nh sounds like ny in canyon, and the final ã is nasal

A rough English-friendly approximation is:

• última → OOL-tee-ma
• lição → lee-SOWN
• amanhã → ah-ma-NYAN

These are only approximations, but they help.

Yes. Explicar often takes both:

• a direct object = the thing being explained
• an indirect object = the person you explain it to

So in this sentence:

• a última lição = direct object
• aos alunos = indirect object

This is a very useful pattern to remember:

• explicar algo a alguém = to explain something to someone