Na sexta-feira, precisamos terminar o trabalho da escola antes do prazo.

Na is a contraction of em + a.

• em = in / on / at (depending on context)
• a = the feminine singular article the

So na sexta-feira literally breaks down as on the Friday, and in natural English we usually just say on Friday.

This is a very common way to talk about days in Portuguese:

• na segunda-feira = on Monday
• na terça-feira = on Tuesday
• na sexta-feira = on Friday

Because sexta-feira is feminine, you use a, which gives na.

The hyphen is standard spelling for the weekday names:

• segunda-feira
• terça-feira
• quarta-feira
• quinta-feira
• sexta-feira

Historically, feira referred to a fair or market day, but in modern Portuguese these are just the normal names of the weekdays. You should learn them as fixed expressions with the hyphen.

Portuguese often drops subject pronouns when the verb ending already makes the subject clear.

Here, precisamos means we need. The ending -amos tells you the subject is nós (we), so nós can be omitted.

• (Nós) precisamos terminar... = We need to finish...

Both are correct, but leaving out nós is very natural in Portuguese.

This is a very common structure in Portuguese:

• a conjugated verb: precisamos
• followed by an infinitive: terminar

So:

• precisamos = we need
• terminar = to finish

Together: we need to finish

In Brazilian Portuguese, precisar + infinitive normally does not use de:

• Precisamos terminar. = We need to finish.

But with a noun, de is common:

• Precisamos de ajuda. = We need help.

In this sentence, trabalho most likely means a school assignment, project, or piece of schoolwork, not a job.

Portuguese trabalho can mean different things depending on context:

• work in a general sense
• job
• assignment / project

Because the sentence says da escola, the meaning is probably something like:

• school assignment
• school project
• homework task

So this is probably not about employment; it is about something for school.

Da is a contraction of de + a:

• de = of / from
• a = the

So:

• da escola = of the school / from the school

In natural English, we would usually not translate it word-for-word. In this sentence, o trabalho da escola most naturally means something like:

• the school assignment
• the school project
• the work for school

So da escola identifies what kind of trabalho it is.

Because antes is normally followed by de:

• antes de = before

And do is the contraction of de + o:

• de + o prazo → do prazo

So:

• antes do prazo = before the deadline

Also, prazo means deadline, time limit, or due date, depending on context.

A useful contrast:

• antes do prazo = before the deadline
• até o prazo = by the deadline

These are close, but not identical. Antes do prazo suggests finishing earlier than necessary.

Yes. Portuguese word order is fairly flexible.

The sentence starts with Na sexta-feira to set the time first:

• Na sexta-feira, precisamos terminar o trabalho da escola antes do prazo.

You could also say:

• Precisamos terminar o trabalho da escola na sexta-feira antes do prazo.

Both are understandable, but the original version sounds very natural because it introduces the time frame right away.

Putting the time expression first often adds emphasis or helps organize the sentence clearly.

By itself, it usually means on Friday, and context tells you whether that means:

• this coming Friday
• a specific Friday already mentioned
• Friday in general within a narrative

If you want to be very explicit, you can say:

• nesta sexta-feira = this Friday

So:

• Na sexta-feira = on Friday
• Nesta sexta-feira = this Friday

You would usually use the plural:

• às sextas-feiras = on Fridays

Examples:

• Na sexta-feira = on Friday
• Às sextas-feiras = on Fridays

Here, às is a contraction of a + as.

So the singular refers to one Friday, while the plural refers to a repeated habit or routine.