Υπάρχει πολλή σκόνη πάνω στο ράφι, γι’ αυτό ξεσκονίζω πριν κάτσω να διαβάσω.

Υπάρχει is the usual way to say there is in Greek. It introduces the existence of something.

Here it is singular because σκόνη (dust) is treated as a singular uncountable noun. So Greek says:

• Υπάρχει πολλή σκόνη = There is a lot of dust

If the noun were plural, you would use υπάρχουν:

• Υπάρχουν πολλά βιβλία = There are many books

Because πολλή has to agree with σκόνη, and σκόνη is feminine singular.

The word πολύς (much/many/a lot of) changes form:

• masculine: πολύς
• feminine: πολλή
• neuter: πολύ

So:

• πολλή σκόνη = a lot of dust
• πολύ νερό = a lot of water
• πολλά βιβλία = many books

English learners often know πολύ as very or a lot, but here you need the adjective form that matches the noun, so πολλή is correct.

It is singular. Greek treats dust as a mass noun, just like English usually does.

That is why the sentence has:

• υπάρχει (singular)
• πολλή (feminine singular)

Even though the idea is a lot of dust, the noun itself is still singular.

It means on the shelf.

Breakdown:

• πάνω = on top / above
• στο = σε + το
• ράφι = shelf

So πάνω στο ράφι is literally something like on top of the shelf.

In everyday Greek, this is a very natural way to say that something is on a surface.

Στο is a contraction of σε + το.

• σε = in, at, to, on
• το = the (neuter singular)

So:

• σε το ράφι becomes στο ράφι

This contraction is standard and very common in Greek:

• στο = σε + το
• στη = σε + τη(ν)
• στον = σε + τον

Γι’ αυτό means so, therefore, or that’s why.

It connects cause and result:

• There is a lot of dust on the shelf, so I dust...

The apostrophe shows that a vowel has been dropped:

• για αυτό → γι’ αυτό

In this sentence, γι’ αυτό works as a fixed linking expression meaning for that reason / that’s why.

It means I dust, I dust off, or I remove dust.

It comes from σκόνη (dust). The prefix ξε- often gives the idea of removing something, so the verb has the sense of getting the dust off.

That is useful because English dust can sometimes be ambiguous, but Greek ξεσκονίζω clearly means remove the dust.

Because the Greek present tense can cover both:

• I dust (habitual)
• I’m dusting (right now)

So ξεσκονίζω can be understood from context. In this sentence, it could sound like:

• So I dust before I sit down to read or
• So I’m dusting before I sit down to read

If you wanted a clear future meaning, Greek would usually use θα:

• θα ξεσκονίσω = I will dust

Because after πριν (before), Greek usually uses a subjunctive-type form, and very often the aorist form is chosen when the action is seen as a single event.

So:

• κάτσω = sit down / settle down as one complete action

By contrast, κάθομαι means I am sitting / I sit, which describes a state or ongoing situation, not the one-time action of sitting down.

Here the meaning is before I sit down to read, so κάτσω is the natural choice.

After πριν, Greek often leaves out να.

So these are both possible in Modern Greek, but the version without να is very common and natural:

• πριν κάτσω
• πριν να κάτσω

In your sentence, πριν κάτσω is completely normal.

As a whole, it means sit down to read or settle down to read.

Literally, it is something like:

• κάτσω = sit down
• να διαβάσω = to read / that I read

But Greek often uses κάθομαι/κάτσω να + verb as a natural expression for starting or settling into an activity.

So:

• κάτσω να διαβάσω = sit down to read
• κάτσε να φάμε = sit down / let’s sit down and eat

Because Greek chooses between different verb forms after να depending on how the action is viewed.

• να διαβάσω presents the reading as a single whole event
• να διαβάζω would suggest something ongoing, repeated, or more process-focused

In this sentence, the speaker means before I sit down and do my reading, so να διαβάσω fits better.

It does not mean past tense here. Even though διαβάσω looks like an aorist form, after να it is a subjunctive form, not a past tense.

Yes, στο ράφι could also work in many contexts.

But πάνω στο ράφι is a bit more explicit and vivid: it makes you picture the dust on top of the shelf surface.

So:

• στο ράφι = on the shelf
• πάνω στο ράφι = on top of the shelf

In this sentence, πάνω helps emphasize where the dust is sitting.