Magbukas ka ng bintana sa kusina para pumasok ang sariwang hangin.

Mag- is a common verb-forming prefix. Here it makes magbukas into an actor-focus verb, meaning the sentence is centered on the person doing the opening.

In a command like this, magbukas means open or do the action of opening.

Ka means you (singular) in the ang/nominative form. With an actor-focus verb like magbukas, the doer is marked with ka.

So magbukas ka is literally something like you open / open, you. This word order is normal in Filipino.

Because magbukas is actor-focus. In actor-focus sentences, the thing affected by the action is often marked by ng.

So:

• Magbukas ka ng bintana = actor-focus
• Buksan mo ang bintana = object/patient-focus

Both can translate naturally into English, but the Filipino grammar is organized differently.

Very often, yes: it can feel more like a window or at least a non-focused / non-emphasized window. But Filipino markers do not match English a/the exactly.

So context matters. Even with ng bintana, speakers may still understand which window is meant.

Sa kusina means in the kitchen. The marker sa is commonly used for location.

In this sentence, it most naturally points to the window/location involved: the window in the kitchen or open a window in the kitchen.

Para means so that or in order that. It introduces a purpose clause.

So para pumasok... means so that ... can enter/come in. This explains the reason for opening the window.

This is a very common learner question. For many -um- verbs, the basic/infinitive-like form and the completed form can look the same.

Here:

• root: pasok = enter/go in
• actor-focus form: pumasok

After para, pumasok is understood as to enter / come in, not as a past action. The context makes that clear.

In the clause pumasok ang sariwang hangin, the fresh air is the one doing the entering, so it is the main noun of that clause. That is why it gets ang.

So in this part:

• pumasok = enter / come in
• ang sariwang hangin = the fresh air

This is because of the linker. Filipino often uses a linker to connect an adjective and the noun it describes.

Since sariwa ends in a vowel, the linker appears as -ng attached to it:

• sariwa
  • -ng → sariwang

So sariwang hangin means fresh air.

A more specific version would usually be:

Buksan mo ang bintana sa kusina para pumasok ang sariwang hangin.

That version uses buksan and ang bintana, which makes the window sound more specific and more directly targeted.

Yes, Magbukas ka... is a fairly direct command to one person. It is normal, but not especially polite.

To make it more polite, you could say:

Magbukas po kayo ng bintana sa kusina para pumasok ang sariwang hangin.

Here, po adds politeness, and kayo is the respectful/plural form of you.