Na quinta-feira, minha mãe vai à farmácia depois do trabalho.

Na is a contraction of em + a.

• em can mean in / on / at, depending on context.
• a is the feminine singular definite article the.

So na quinta-feira literally comes from em a quinta-feira, and it means on Thursday.

In Portuguese, days of the week are often used with an article after a preposition, so na quinta-feira is a very natural way to say on Thursday.

In Portuguese, the weekday names segunda-feira, terça-feira, quarta-feira, quinta-feira, sexta-feira are normally written with a hyphen.

They are also usually not capitalized, unlike in English. So:

• quinta-feira = correct in normal writing
• Quinta-feira = only if it starts a sentence or appears in a title style

That is one of the small but important spelling differences between English and Portuguese.

Both are possible in Brazilian Portuguese:

• minha mãe
• a minha mãe

The article before a possessive is often optional in Brazilian Portuguese, and usage can vary by region, style, and context.

So minha mãe vai... is completely natural.
If you said a minha mãe vai..., that would also be correct.

This is one of the most common questions learners ask.

À is the contraction of:

• a = the preposition used after ir in more standard Portuguese
• a = the feminine singular article before farmácia

So:

• ir a + a farmácia
• becomes ir à farmácia

This process is called crasis.

The accent in à is a grave accent, not the same as the acute accent in words like mãe or farmácia. It marks that two a sounds have merged into one written form.

A helpful comparison:

• ao banco = a + o banco
• à farmácia = a + a farmácia

Yes, but there is a difference in register and nuance.

• vai à farmácia = very standard; often taught as the preferred form after ir
• vai para a farmácia = also correct; often feels a bit more like goes toward / goes to
• vai na farmácia = very common in spoken Brazilian Portuguese, but less formal and not usually preferred in careful writing

So for learners, vai à farmácia is an excellent model to know.

Because depois is normally followed by the preposition de.

So the structure is:

• depois de + noun
• depois de + verb

Here, the noun is o trabalho, so:

• depois de o trabalho
• becomes depois do trabalho

That is because de + o = do.

So:

• depois do trabalho = after work
• depois de trabalhar = after working

Grammatically, vai is present tense of the verb ir:

• eu vou
• você / ele / ela vai

But in Portuguese, the present tense is often used for a planned or scheduled future action, especially when there is a time expression like na quinta-feira.

So depending on context, this sentence can mean something like:

• My mother goes to the pharmacy on Thursday after work
• or My mother is going / will go to the pharmacy on Thursday after work

Portuguese often lets the time expression do the job of showing whether something is present, habitual, or future.

Portuguese word order is flexible, and time expressions are very often placed at the beginning of the sentence.

Starting with Na quinta-feira sets the time frame first. It is similar to English sentences like:

• On Thursday, my mother...

You could also move it:

• Minha mãe vai à farmácia depois do trabalho na quinta-feira.

That is possible, but the original order sounds very natural and clear.

The word farmácia has an acute accent to show the stressed syllable:

• far-MÁ-ci-a

It is pronounced with the stress on má.

Also, words of this stress pattern in Portuguese are commonly written with an accent. So the accent is part of the correct spelling and helps you pronounce the word properly.

Because the subject is already stated: minha mãe.

So there is no need to add ela:

• Minha mãe vai à farmácia... = natural
• Ela vai à farmácia... = also natural if the subject was already clear from previous context
• Minha mãe ela vai... = possible in some spoken styles for emphasis, but not the neutral standard form here

Portuguese often leaves subject pronouns out when the subject is already expressed or understood.

In this sentence, trabalho is best understood as work in the sense of the workday / being at work.

So depois do trabalho usually means:

• after work
• after getting off work

It does not necessarily focus on the specific job itself. It is a very common everyday expression.