Повіка закриває око.

• повіка = a/the eyelid
  
  • noun, feminine, singular, nominative case
• закриває = closes / is closing
  • verb, 3rd person singular, present tense
• око = eye
  • noun, singular, accusative case here as the direct object

So the basic structure is:

subject + verb + object
повіка + закриває + око

It is in the object case, but for this noun the form happens to stay the same.

Око is a neuter inanimate noun. In Ukrainian, the accusative singular of many inanimate neuter nouns is identical to the nominative singular.

So:

• nominative: око
• accusative: око

That is why you do not see a different ending here.

Because it is the 3rd person singular present form: he/she/it closes.

The verb is закривати = to close / to be closing.
Its present-tense forms include:

• я закриваю = I close / am closing
• ти закриваєш = you close / are closing
• він / вона / воно закриває = he / she / it closes / is closing

Since повіка is singular, the verb is also singular: закриває.

It can mean either one, depending on context.

Ukrainian present tense often covers both:

• closes
• is closing

So Повіка закриває око could be understood as:

• The eyelid closes the eye
• The eyelid is closing the eye

English forces you to choose more often than Ukrainian does.

Закриває comes from закривати, which is imperfective.

That means it can describe:

• an ongoing action
• a repeated action
• a general fact

Its perfective partner is закрити.

Compare:

• закривати / закриває = to close, to be closing
• закрити / закриє = to close completely, will close

So:

• Повіка закриває око = the eyelid closes / is closing the eye
• Повіка закриє око = the eyelid will close the eye

Because Ukrainian has no articles.

A sentence like Повіка закриває око can mean:

• The eyelid closes the eye
• An eyelid closes an eye
• sometimes even a more general Eyelid closes eye, depending on context

English needs articles; Ukrainian normally does not. The exact meaning comes from context.

The given order is the most neutral one: subject–verb–object.

But Ukrainian word order is fairly flexible because case endings help show the grammatical roles.

For example:

• Повіка закриває око. = neutral
• Око закриває повіка. = the same basic meaning, but with more focus on око

Even when the order changes, повіка is still the subject because it is in the nominative form, while око is understood as the object.

No. Ukrainian normally uses закривати + direct object.

So:

• закривати двері = to close the door
• закривати очі = to close the eyes
• закривати око = to close the eye

English may sometimes say close over the eye in a more descriptive way, but Ukrainian does not need a preposition here.

The stress is:

• пові́ка
• закрива́є
• о́ко

A rough pronunciation guide:

po-VEE-ka za-kry-VA-ye O-ko

A few notes:

• в in повіка is like a Ukrainian v/w-like sound
• и in закриває is not exactly English ee; it is a shorter, central sound
• є in -ває sounds like ye

Yes. Повіка is the normal word for eyelid.

Useful related forms:

• повіка = eyelid
• повіки = eyelids
• око = eye
• очі = eyes

A common beginner mistake is confusing повіка with вія:

• повіка = eyelid
• вія = eyelash

So in this sentence, повіка definitely means eyelid, not eyelash.