Τα υποδήματα είναι καθαρά.

Τα is the definite article meaning the.

In this sentence, τα goes with υποδήματα because υποδήματα is:

• neuter
• plural
• here in the nominative case, because it is the subject of the sentence

So:

• το υπόδημα = the shoe / the item of footwear (singular)
• τα υποδήματα = the shoes / the footwear (plural)

Greek usually requires the article in places where English may or may not use the.

Υποδήματα is plural.

Its singular form is υπόδημα.

So:

• το υπόδημα = singular
• τα υποδήματα = plural

The ending -ματα is a very common neuter plural ending in Greek.

In Modern Greek, είναι means both:

• is
• are

So Greek does not distinguish between he/she/it is and they are in this verb form.

Examples:

• Το υπόδημα είναι καθαρό. = The shoe is clean.
• Τα υποδήματα είναι καθαρά. = The shoes are clean.

In both sentences, the verb is still είναι.

Because καθαρά must agree with υποδήματα.

Since υποδήματα is:

• neuter
• plural

the adjective must also be:

• neuter
• plural

That is why we get:

• καθαρός = masculine singular
• καθαρή = feminine singular
• καθαρό = neuter singular
• καθαρά = neuter plural

So:

• το υπόδημα είναι καθαρό = singular
• τα υποδήματα είναι καθαρά = plural

Not always. Καθαρός / καθαρή / καθαρό / καθαρά can have several related meanings depending on context, such as:

• clean
• clear
• pure

But with υποδήματα, the natural meaning is clean.

So in this sentence, καθαρά is understood as clean.

It is correct Greek, but it is a bit more formal or general than the everyday word many learners hear first.

A more common everyday word is:

• παπούτσια = shoes

So:

• Τα παπούτσια είναι καθαρά. is often more natural in everyday conversation.
• Τα υποδήματα είναι καθαρά. sounds more formal, technical, or written.

Υποδήματα can also refer more broadly to footwear, not just shoes in the narrow sense.

Because this sentence is using καθαρά as a predicate adjective, not as an adjective placed directly inside the noun phrase.

Compare:

1. Τα υποδήματα είναι καθαρά.
   = The shoes are clean.
   Here, clean is part of what is being said about the subject.

2. Τα καθαρά υποδήματα
   = the clean shoes
   Here, clean is directly describing the noun inside the noun phrase.

So both patterns exist in Greek, just as they do in English.

Yes. Greek word order is more flexible than English word order.

The neutral order here is:

• Τα υποδήματα είναι καθαρά.

But other orders are possible for emphasis, for example:

• Καθαρά είναι τα υποδήματα.
• Είναι καθαρά τα υποδήματα.

These alternatives may sound more marked or emphatic depending on context. For basic learning, the original order is the safest and most neutral.

Normally, in a standard full sentence like this, είναι is included.

So:

• Τα υποδήματα είναι καθαρά. is the normal full sentence.

You may sometimes see omission of είναι in:

• headlines
• labels
• notes
• very compressed style

But for ordinary sentence building, learners should include it.

You know from both meaning and form.

• Τα υποδήματα has the article and noun in the nominative plural
• καθαρά is an adjective agreeing with that noun
• είναι links the subject to the description

So the structure is:

• Τα υποδήματα = subject
• είναι = linking verb
• καθαρά = predicate adjective

This is exactly the same basic pattern as The shoes are clean.

The stress falls on δή:

• υποδήματα → roughly ee-po-THEE-ma-ta
• καθαρά → roughly ka-tha-RA

A few useful points:

• Greek stress matters, so the accent marks show which syllable is stressed.
• In υποδήματα, the accented syllable is δή.
• In καθαρά, the accented syllable is the last one: ρά.

Yes, the key words match in the way Greek grammar requires.

• τα = plural article
• υποδήματα = plural noun
• καθαρά = plural adjective

The verb είναι does not visibly change between is and are, but the sentence is still clearly plural because of the noun phrase and adjective agreement.

So the plural meaning is shown mainly by:

• τα
• υποδήματα
• καθαρά