Learn Hardcore Portuguese (Portugal): A professora vai explicar-lhe o exercício depois do exame. - The teacher is going to explain the exercise to him/her after the exam.

In Portuguese, unstressed object pronouns like lhe are written attached to the verb with a hyphen when they follow the verb. This is called enclisis.

Here:

explicar = to explain
lhe = to him/her/you
explicar-lhe = to explain to him/her/you

Because lhe comes after the infinitive explicar, we join them:

explicar + lhe → explicar-lhe

This is a standard spelling rule in European Portuguese:

dar + lhe → dar-lhe (to give to him/her/you)
mostrar + nos → mostrar-nos (to show us)
dizer + te → dizer-te (to tell you – informal)

Why is the pronoun attached to explicar and not to vai? Why vai explicar-lhe and not vai-lhe explicar in writing?

With ir + infinitive (the “going to” future), the standard written pattern in European Portuguese is to attach the pronoun to the infinitive, not to ir:

A professora vai explicar-lhe o exercício. ✅ (standard)
A professora vai-lhe explicar o exercício. ✅ (very common in speech, less formal in writing)

So you have three realistic patterns in European Portuguese:

Standard, neutral:
- A professora vai explicar-lhe o exercício.
Very common in spoken Portuguese (and also seen in informal writing):
- A professora vai-lhe explicar o exercício.
When something attracts the pronoun to the left (negation, certain adverbs, etc.), it normally comes before the auxiliary vai:
- A professora não lhe vai explicar o exercício.
- A professora já lhe vai explicar o exercício.

So:

In careful written Portuguese, attach lhe to explicar.
In everyday speech, vai-lhe explicar is also very natural.

Could I use te instead of lhe here? What would change?

Yes, you can change lhe to te, but it changes the register and the person:

A professora vai explicar-te o exercício depois do exame.

Here:

te = to you (informal “tu”)
lhe = to you (formal você / o senhor / a senhora) or to him / to her

Differences:

te is used when speaking informally to someone you call tu (friend, child, often family).
lhe is used:
- for formal “you” (você / o senhor / a senhora), or
- for he/she (to him / to her).

So:

Talking to a friend: A professora vai explicar-te o exercício…
Talking in a formal tone or about a third person: A professora vai explicar-lhe o exercício…

Is vai explicar a future tense? Why not use explicará?

Vai explicar is a periphrastic future:

vai = present of ir (to go)
explicar = infinitive (to explain)
Meaning: “is going to explain / will explain”

You could also say:

A professora explicará o exercício depois do exame. ✅

Differences in European Portuguese:

vai explicar
- more common in everyday speech,
- feels neutral and modern, like English “is going to explain / will explain”.
explicará
- more formal or literary,
- used more in writing, news language, or very formal speech.

In practice, for normal conversation and most writing, vai explicar is preferred.

Why is it o exercício and not just exercício without the article?

Portuguese uses definite articles more than English.

o exercício = the exercise (a specific one, known in context)
bare exercício (with no article) is much less common and would sound incomplete here.

In this sentence, both speaker and listener know which exercise is being talked about (for example, the one on the exam or in the textbook), so Portuguese naturally uses the definite article:

A professora vai explicar-lhe o exercício…
→ The teacher is going to explain the exercise (that specific one)…

You would drop the article mainly in:

titles or labels: Exercício 3
some fixed expressions / very generic statements.

What is the role of depois de and why is it do exame instead of de o exame or just depois o exame?

Depois de is the usual way to say “after” with a noun or verb:

depois de
- noun: depois do exame = after the exam
depois de
- verb in infinitive: depois de estudar = after studying

Now, do is a contraction:

de + o = do

So:

depois de + o exame → depois do exame

You cannot say:

✖ depois o exame (missing de)
✖ depois de o exame (grammatical but almost never used; we normally contract to do)

Other similar contractions:

de + a → da (fem. sing.) → depois da aula (after the class)
de + os → dos → depois dos testes (after the tests)
de + as → das → depois das férias (after the holidays)

Can I move depois do exame to another place in the sentence?

Yes. Time expressions like depois do exame are quite flexible. All of these are acceptable:

Depois do exame, a professora vai explicar-lhe o exercício.
A professora vai explicar-lhe, depois do exame, o exercício. (more formal / written)
A professora vai explicar-lhe o exercício depois do exame. (your original order)

Normal, natural orders are:

At the beginning for emphasis on time:
- Depois do exame, a professora vai explicar-lhe o exercício.
At the end, which is probably the most neutral:
- A professora vai explicar-lhe o exercício depois do exame.

Why is it a professora and not o professor? Does the article change with gender?

Yes, both the noun and the article change with gender in Portuguese.

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

Pattern:

Masculine singular: o
- masculine noun
Feminine singular: a
- feminine noun

So here:

professor → feminine form professora
o → feminine article a

Hence: a professora (the female teacher).

If I want to avoid lhe, how could I say this sentence more explicitly?

You can replace lhe with a full prepositional phrase starting with a:

Examples:

A professora vai explicar o exercício a ele depois do exame.
→ to him
A professora vai explicar o exercício a ela depois do exame.
→ to her
A professora vai explicar o exercício a você depois do exame.
→ to you (formal “você”, more common in Brazil; in Portugal it can sound distant or a bit brusque)
A professora vai explicar o exercício ao senhor / à senhora depois do exame.
→ to you, sir / to you, ma’am (very polite/formal)

This is useful when you want to avoid ambiguity about who lhe refers to.

How do I pronounce lhe in European Portuguese?

In European Portuguese:

lh represents a palatal “L” sound, like the “lli” in English “million” (but a bit clearer).
lhe is usually pronounced approximately like [lye] or [ʎɨ] (short, light vowel at the end).

Tips:

Put your tongue against the palate, like for “ll” in “million”.
Make a quick ly sound and add a very short, neutral vowel: ly(uh).

So explicar-lhe sounds roughly like:

esh-plee-KAR-lye (very approximate English-style representation).

If I want to say “The teacher is not going to explain the exercise to him”, where does não go with lhe?

With negation, não usually pulls the pronoun before the verb it directly affects. With ir + infinitive, two very natural options in European Portuguese are:

Pronoun before vai (quite common):
- A professora não lhe vai explicar o exercício depois do exame.
Pronoun attached to the infinitive (also correct):
- A professora não vai explicar-lhe o exercício depois do exame.

In practice, option 1 (não lhe vai explicar) is very frequent in EP, especially in speech, but both are grammatically acceptable.