Mas gusto ni Ana ang bolpen kaysa lapis kapag pumipirma siya sa papel.

Yes. Mas gusto is the most common everyday way to express prefer in Filipino.

Literally:

• gusto = like / want
• mas = more

So Mas gusto ni Ana ang bolpen kaysa lapis is literally something like Ana likes the pen more than the pencil, which is how Filipino usually expresses Ana prefers the pen to the pencil.

There is no single everyday verb that matches English prefer perfectly as often as mas gusto does.

Because in a gusto sentence, the person who feels the liking or preference is usually marked with ni for a name, or ng for a common noun.

So:

• Gusto ni Ana ang bolpen = Ana likes the pen
• Gusto ng bata ang kendi = The child likes candy

This is different from many basic Filipino sentences where a person might be marked by si. With gusto, the grammar works differently:

• the experiencer or liker is marked by ni/ng
• the thing liked is marked by ang

In this kind of sentence, the thing being liked or preferred is marked with ang.

So in:

• Mas gusto ni Ana ang bolpen...

the item Ana prefers is ang bolpen.

For English speakers, this can feel backwards at first, because English would usually treat Ana as the subject. In Filipino, though, gusto commonly puts the preferred thing in the ang phrase, while the person who has the preference is marked with ni/ng.

Both kaysa lapis and kaysa sa lapis can be heard.

• kaysa lapis = shorter, very common
• kaysa sa lapis = also correct, slightly fuller

Kaysa means than in comparisons.

So:

• Mas gusto ni Ana ang bolpen kaysa lapis
• Mas gusto ni Ana ang bolpen kaysa sa lapis

Both mean the same thing here: Ana prefers the pen over the pencil.

No. After kaysa, the compared item does not need ang here.

So:

• ang bolpen = the item being preferred
• kaysa lapis = than pencil

The first noun is the main item in the preference structure, and the second noun is just the comparison point.

Kapag means when or whenever, often with the sense of in the situation that or every time that depending on context.

In this sentence:

• kapag pumipirma siya sa papel = when / whenever she signs on paper

It introduces the situation in which the preference applies.

So the sentence does not mean Ana always prefers a pen in every possible context; it specifically says that this preference applies when she is signing on paper.

Pumipirma is the imperfective form of the verb, which often expresses:

• an ongoing action
• a repeated action
• a habitual action

Here that makes sense because the sentence is talking about what Ana prefers when she signs.

Related forms:

• pumirma = signed
• pumipirma = is signing / signs
• pipirma = will sign

The root is pirma, and the verb means to sign.

Because once Ana has already been introduced, Filipino often uses a pronoun naturally afterward.

So:

• Mas gusto ni Ana... kapag pumipirma siya...

is smoother than repeating the name again:

• Mas gusto ni Ana... kapag pumipirma si Ana...

Using siya is normal and natural, just like English often says Ana prefers the pen when she signs instead of repeating Ana twice.

That is a normal Filipino word order.

In Filipino, the predicate or verb often comes first, so:

• pumipirma siya = she signs / she is signing

You could also hear a more expanded structure like:

• kapag siya ay pumipirma sa papel

but that sounds a bit more formal or emphatic. The shorter kapag pumipirma siya sa papel is very natural in everyday usage.

Sa is used here to mark the location or surface involved: on the paper.

So:

• pumipirma siya sa papel = she signs on the paper

That is why sa is appropriate. It points to the place or surface where the signing happens.

If you used ng papel instead, it would not sound right for this meaning.

Yes. Filipino word order is fairly flexible because markers like ni, ang, and sa show the roles of the words.

For example, you could also say:

• Kapag pumipirma siya sa papel, mas gusto ni Ana ang bolpen kaysa lapis.

That means basically the same thing. The difference is mainly what comes first for flow or emphasis.

The original sentence starts with the preference:

• Mas gusto ni Ana ang bolpen...

The reordered version starts with the situation:

• Kapag pumipirma siya sa papel...

Yes, bolpen is a very common Filipino spelling based on English ballpen.

In everyday speech, many people say:

• bolpen
• sometimes ballpen

Both are widely understood. In this sentence, bolpen is completely natural.

By contrast, lapis is the ordinary word for pencil.

Yes, in many contexts it could.

• kapag = when / whenever
• tuwing = every time

So:

• Mas gusto ni Ana ang bolpen kaysa lapis kapag pumipirma siya sa papel.
• Mas gusto ni Ana ang bolpen kaysa lapis tuwing pumipirma siya sa papel.

The second version sounds a little more clearly habitual: every time she signs on paper.
The original with kapag is still very natural and can also carry that repeated meaning from context.