Pe perdea este mult praf, așa că Ana o șterge acum.

Here pe means on: pe perdea = on the curtain.

It is not the direct-object marker you see in sentences like O văd pe Ana. Romanian uses the same word pe for both things, so you have to tell from context:

• pe perdea = a location phrase
• o șterge = the actual direct object part of the sentence

So in this sentence, pe perdea simply tells you where the dust is.

Romanian often allows a bare noun after a preposition when the noun is just naming a place or surface, especially when the exact identity is not the main point.

So pe perdea can sound natural for on the curtain / on the curtain surface.

If you want to make the curtain more explicitly definite or more specific, Romanian can also do that, for example:

• pe perdeaua din sufragerie = on the curtain in the living room
• pe perdeaua aceea = on that curtain

For a learner, the important point is: Romanian is sometimes a bit less strict than English about using the definite article in location phrases.

Yes, Este mult praf pe perdea is also correct and probably feels more neutral.

Starting with Pe perdea puts the location first for emphasis or topic:

• Pe perdea este mult praf = As for the curtain / On the curtain, there is a lot of dust

Romanian word order is more flexible than English word order, so moving pe perdea to the front is normal.

Romanian often uses este by itself in sentences where English uses there is.

So:

• Este mult praf literally = is much dust
• natural English = There is a lot of dust

Romanian does not need a separate dummy word like English there in this kind of sentence.

Also, in everyday speech, este is often shortened to e:

• Pe perdea e mult praf

Because praf is treated as an uncountable noun here, like dust in English.

So Romanian uses the singular mass-noun pattern:

• mult praf = a lot of dust

Compare:

• mult lapte = a lot of milk
• mult timp = a lot of time

The form of mult changes depending on gender and number:

• mult praf — masculine/neuter singular
• multă apă — feminine singular
• mulți oameni — masculine plural
• multe cărți — feminine/neuter plural

You would not normally say prafuri here, because that would mean different kinds or amounts of dust as separate countable items, which is not what this sentence is talking about.

Așa că means so, therefore, or that’s why.

It links the two parts of the sentence:

• there is a lot of dust on the curtain
• so Ana wipes it now

It is a very common Romanian connector for showing result.

O is the unstressed direct-object pronoun meaning it.

It refers back to perdea, which is a feminine singular noun. Because perdea is feminine singular, the pronoun is also feminine singular:

• perdea → o

So:

• Ana o șterge = Ana wipes it

Romanian often uses a pronoun instead of repeating the noun when the thing has just been mentioned.

In normal declarative sentences, Romanian unstressed object pronouns usually come before the conjugated verb:

• Ana o șterge
• Îl vede
• Le cumpără

So o șterge is the expected order.

After the verb, you often see these pronouns with positive imperatives:

• Șterge-o! = Wipe it!

That is why Ana o șterge is correct here, not Ana șterge-o.

It can mean either, depending on context.

Romanian present tense often covers both:

• simple present: wipes
• present progressive: is wiping

Here, acum makes the ongoing meaning clear:

• Ana o șterge acum = Ana is wiping it now

So Romanian does not need a special verb form like English is wiping.

Yes. That is also correct.

Compare:

• Ana o șterge acum = Ana is wiping it now
• Ana șterge perdeaua acum = Ana is wiping the curtain now

The version with o sounds more natural when the curtain has already been mentioned, because it avoids repeating the noun.

So the original sentence is using a very normal Romanian strategy:

1. mention the noun first: perdea
2. refer back to it with a pronoun: o

Two sounds often stand out for English speakers:

• ș sounds like English sh

  • așa
  • șterge

• ă is a short central vowel, something like the a in sofa, but shorter and weaker

  • așa
  • că

A rough learner-friendly pronunciation guide:

• Pe perdea ≈ pe per-DE-a
• așa că ≈ a-SHA kuh
• șterge ≈ SHTER-jeh

Also note that ge in șterge sounds like the j in job, not like a hard g.