Noong isang linggo, nilagnat si Maria at hindi siya nakapasok sa opisina.

Isang is the form of isa used directly before a noun. The -ng is a linker that connects isa to linggo. So:

• isa = one
• isang linggo = one week

This is very common in Filipino:

• isang araw = one day
• isang bata = one child

Si is the personal marker used for a singular person’s name when that person is the sentence topic or focus. Since Maria is the person being talked about, si Maria is the natural form.

Compare:

• si Maria = Maria as the marked person/topic
• ang babae = the woman as a common noun topic

So si is not the word for she; it is a marker used before a person’s name.

Nilagnat means had a fever or got a fever. It comes from lagnat, which means fever.

This is a very common Filipino way to describe health conditions: a noun can become a verb-like form meaning to experience that condition. So rather than saying something very literal like was fevered, Filipino naturally says nilagnat.

It is best to learn nilagnat as a whole expression meaning came down with a fever / had a fever.

Yes, but the nuance is a little different.

• May lagnat si Maria = Maria has a fever
• Nilagnat si Maria = Maria got/had a fever

May lagnat describes the condition more statically. Nilagnat sounds more event-like, as if the fever happened to her or came on. In this sentence, nilagnat fits well because the sentence is telling what happened last week.

At simply means and. It links the two parts of the sentence:

• nilagnat si Maria
• hindi siya nakapasok sa opisina

In everyday speech, some speakers may use saka or tsaka in casual conversation, but at is the standard neutral conjunction in writing.

Once Maria has already been introduced, Filipino naturally uses the pronoun siya for he/she in the next clause.

So instead of repeating Maria, the sentence says:

• hindi siya nakapasok sa opisina

This is similar to English using she after already mentioning Maria. Repeating Maria would still be possible, but siya sounds smoother and more natural.

Also, siya is the correct pronoun here because it matches the role that Maria had in the first clause.

Literally, nakapasok comes from pasok, which has the basic idea of entering or going in. But in work or school contexts, pumasok or nakapasok often means to come in, to attend, or to make it to work or school.

So here, hindi siya nakapasok sa opisina does not just mean she did not physically enter the office building. It more naturally means:

• she couldn’t come to the office
• she wasn’t able to go to work
• she didn’t make it into the office

The exact English wording depends on context, but the idea is that she was absent from work because of the fever.

Hindi usually comes before the part it negates. In a neutral sentence, hindi siya nakapasok is the normal word order.

So the structure is:

• hindi = not
• siya = she
• nakapasok = was able to come in / got in

Putting siya before hindi would sound unusual or strongly marked in standard Filipino unless there is a special contrastive context. For normal statements, hindi siya nakapasok is the form learners should use.

Sa is the marker commonly used for places, locations, and destinations. Since opisina is a place, sa opisina means to the office or at the office, depending on context.

Here it works as the destination/location connected with nakapasok:

• nakapasok sa opisina = got into / made it to the office

So sa is used because the office is a place, not because it is a direct object.

Filipino is usually described as marking aspect more than tense. That means the verb forms mainly show whether an action is completed, ongoing, or contemplated, rather than simply past, present, or future in the English way.

This sentence is understood as past because of two things:

• Noong isang linggo clearly places the situation in the past.
• nilagnat presents the fever as something that happened.
• hindi siya nakapasok is also interpreted in that past context.

So even if Filipino does not work exactly like English tense systems, the whole sentence is definitely understood as talking about a past event.

Yes, Filipino word order is fairly flexible. For example, you could say:

Nilagnat si Maria noong isang linggo at hindi siya nakapasok sa opisina.

That is still grammatical. However, starting with Noong isang linggo is very natural because it immediately tells the listener when the events happened. It is a common storytelling pattern in Filipino to place the time expression first.