Ayer la vecina cambió el felpudo porque la cerradura no cerraba bien y entraba mucho polvo.

This is one of the most important grammar points in the sentence.

• cambió = preterite
  This presents the action as a completed event: the neighbor changed the doormat.

• cerraba and entraba = imperfect
  These describe the background situation or an ongoing/problematic condition:

  • the lock wasn’t closing properly
  • a lot of dust was coming in

So the structure is:

• main completed action: Ayer la vecina cambió el felpudo
• reason/background: porque la cerradura no cerraba bien y entraba mucho polvo

In English, we often use simple past for all of these, but Spanish makes a clearer distinction between:

• what happened once → preterite
• what was going on / what the situation was → imperfect

Ayer means yesterday.

It sets the time frame right away, and it also strongly suggests the use of the preterite for the main action, because it refers to a finished time period in the past.

So:

• Ayer → finished past time
• cambió → completed action in that finished past time

This combination is very common in Spanish:

• Ayer fui al médico
• Ayer compré pan
• Ayer la vecina cambió el felpudo

In Spanish, it is very common to use the definite article with nouns where English might use nothing or a possessive.

So la vecina means:

• the neighbor
• or, depending on context, the woman next door / the neighbor woman

Spanish often uses the article when referring to a known person in the context:

• La profesora dijo...
• El médico me llamó
• La vecina cambió el felpudo

It does not mean my neighbor unless the context makes that clear. It simply means the neighbor.

Yes.

• vecino = male neighbor, or neighbor in a general masculine form
• vecina = female neighbor

So this sentence tells you that the neighbor is a woman.

Felpudo means doormat.

It is the mat placed at the entrance of a house or flat, usually for wiping your shoes.

In Spain, felpudo is the normal everyday word for this.

The accent mark is important because it shows both pronunciation and verb form.

• cambió = he/she/it changed or you changed (formal singular), preterite
• cambio = I change / I am changing in the present, or the noun change

So:

• cambió = past, third person singular
• cambio = present, first person singular, or a noun

That accent changes the meaning.

Because here it means because.

Spanish distinguishes these forms:

• porque = because
• por qué = why
• el porqué = the reason
• por que = less common combination in other structures

In this sentence, the second clause gives the reason:

• cambió el felpudo porque...
  = she changed the doormat because...

So porque is the correct form.

That is a very natural Spanish way to express it.

• cerradura = lock
• cerrar = to close / to shut

In Spanish, you can say a lock, door, window, etc. cierra or no cierra bien when it does not shut properly.

So la cerradura no cerraba bien means something like:

• the lock wasn’t closing properly
• the lock wasn’t shutting properly
• depending on context, even the lock wasn’t working properly

It sounds a bit different from English, but it is normal Spanish.

Each verb has its own subject.

• la cerradura no cerraba bien
  Subject: la cerradura
  Verb: cerraba → singular

• entraba mucho polvo
  Subject: mucho polvo
  Verb: entraba → singular

So the sentence is not saying one plural subject did two actions. It has:

1. the lock was not closing properly
2. a lot of dust was coming in

Both subjects are singular:

• la cerradura
• mucho polvo

Because polvo here is being used as an uncountable noun, like dust in English.

So:

• mucho polvo = a lot of dust

You do not need an article here, just as in English you usually say:

• a lot of dust not
• a lot of the dust unless you mean specific dust already identified

Compare:

• Entraba mucho polvo = a lot of dust was coming in
• Entraba el polvo del patio = the dust from the patio was coming in

The subject is mucho polvo.

Spanish often puts the subject after the verb, especially when introducing something that appears, enters, happens, etc.

So:

• entraba mucho polvo literally has the order:
• was entering a lot of dust

But in natural English we say:

• a lot of dust was coming in

This is very common in Spanish:

• Llegó un amigo
• Entró agua
• Salía humo
• Entraba mucho polvo

Because Spanish often leaves out subjects when they are clear from context, and it also allows different sentence structures from English.

After y, the sentence simply continues:

• ...la cerradura no cerraba bien y entraba mucho polvo

There is no need to add something like y el polvo entraba mucho unless the speaker wants to emphasize it.

Spanish tends to avoid unnecessary repetition.

In standard Spanish from Spain, ayer usually goes with the preterite, not the present perfect.

So:

• Ayer cambió el felpudo = natural and standard

Using ha cambiado with ayer is generally not the usual choice in standard Peninsular Spanish.

A quick rule for Spain:

• finished past time like ayer, la semana pasada, en 2023 → usually preterite
• time connected to the present like hoy, esta semana, este mes → often present perfect

So:

• Ayer cambió el felpudo
• Hoy ha cambiado el felpudo

Bien means well, and here it modifies the verb cerraba.

So:

• no cerraba bien = it wasn’t closing properly / well

This is a very common pattern in Spanish:

• funciona bien = it works well
• abre bien = it opens properly
• no cierra bien = it doesn’t close properly

English often prefers properly in these cases, while Spanish commonly uses bien.

In this sentence, polvo simply means dust, and that is the meaning you should focus on here.

However, learners often hear that polvo can also appear in some colloquial expressions with other meanings, especially in informal speech. That is true, but it is completely unrelated here.

So in this sentence:

• mucho polvo = a lot of dust

Nothing unusual or humorous is intended.

Yes, that would also be possible, but it would mean something slightly different.

• la cerradura no cerraba bien = the problem is with the lock
• la puerta no cerraba bien = the problem is with the door as a whole

Spanish can describe the issue from different angles depending on what exactly is malfunctioning.

So the original sentence is specifically pointing to the lock as the source of the problem.