A Maria limpou o para-brisas por dentro, sem que a chuva entrasse no carro.

In European Portuguese, it is very common to use the definite article before a person's name: a Maria, o João, a Ana.

So A Maria limpou... sounds normal in Portugal. For an English speaker, this feels unusual because English normally says just Maria.

The article is often left out:

• in direct address: Maria, vem cá
• in some very formal contexts
• in certain titles or headings

But in ordinary speech and neutral writing, A Maria is perfectly natural.

Limpou is the pretérito perfeito simples of limpar.

It means the action is viewed as a completed event in the past:

• A Maria limpou o para-brisas = Maria cleaned the windscreen.

This is different from:

• limpava = was cleaning / used to clean / cleaned repeatedly

So here the sentence presents one finished action.

Para-brisas is a compound noun meaning windscreen / windshield. It is normally written with a hyphen.

Even though brisas looks plural, the whole compound is singular here:

• o para-brisas = the windscreen

In the plural, it often stays the same:

• os para-brisas

So the word may look plural to an English speaker, but in this sentence it is singular.

Here por dentro means on the inside or from the inside.

So:

• limpou o para-brisas por dentro

means Maria cleaned the inside surface of the windscreen, not the outside.

The usual opposite is:

• por fora = on the outside

Usually yes, or at least it strongly suggests that. But the main point of por dentro is to tell you which side of the windscreen was cleaned.

So the focus is:

• the inside face of the windscreen

not mainly:

• Maria's exact physical location

Sem que a chuva entrasse no carro is a subordinate clause that adds an extra circumstance to the main action.

In Portuguese, it is very natural to put a comma before this kind of clause when it comes after the main clause:

• A Maria limpou o para-brisas por dentro, sem que...

The comma helps separate the main action from the added idea. In writing, this is standard and natural here.

Because this part of the sentence has its own subject: a chuva.

With sem + infinitive, the subject is usually the same as in the main clause:

• A Maria saiu sem falar.
  • Maria left without speaking.

But here the second action belongs to the rain, not to Maria:

• sem que a chuva entrasse...

So sem que + subjunctive is the normal structure.

After sem que, Portuguese normally uses the subjunctive.

That is because the clause does not present something as a simple fact. It presents something as prevented, avoided, or not happening:

• sem que a chuva entrasse no carro

Since the main verb is in the past (limpou), the usual form is the imperfect subjunctive:

• entrasse

Compare:

• present/future frame: sem que a chuva entre
• past frame: sem que a chuva entrasse

So entrasse is the expected form here.

Portuguese often uses the definite article where English would not.

Here a chuva means the rain in that situation. It sounds natural and standard:

• sem que a chuva entrasse no carro

Leaving out the article would sound wrong here in normal Portuguese.

Yes, but Portuguese and English use different structures.

In Portuguese, entrar normally goes with em when you say where something goes:

• entrar no carro
• entrar na sala

Here:

• no = em + o

So:

• entrasse no carro = entered/got into the car

Even though English can say just enter the car, Portuguese normally uses entrar em + place or vehicle.