Nakrętka leży obok butelki.

Because obok requires the genitive case.

• dictionary form: butelka = bottle
• after obok: obok butelki = next to / beside the bottle

This is a very common pattern in Polish:

• obok domu = next to the house
• obok stołu = next to the table
• obok butelki = next to the bottle

So the ending changes because of grammar, not because the meaning of bottle changes.

It is the genitive singular of butelka.

Butelka is a feminine noun, and feminine nouns ending in -a often change to -i or -y in the genitive singular.

So:

• nominative: butelka
• genitive: butelki

In this sentence, obok triggers the genitive, so butelki is the correct form.

Obok usually means next to, beside, or by the side of. It often suggests fairly close physical position.

So obok butelki means the cap is right beside the bottle, not just somewhere in the general area.

If you want a looser idea like near, Polish often uses blisko:

• obok butelki = beside the bottle
• blisko butelki = near the bottle

Polish often prefers a more specific verb for location than English does.

Leży comes from leżeć, which means to lie. It is used for something that is in a lying/resting position, especially on a surface.

So:

• Nakrętka leży obok butelki = the cap is lying next to the bottle

A Polish speaker would often choose leży because it sounds more natural and more precise than simply using is.

Compare:

• Książka leży na stole. = The book is lying on the table.
• Telefon leży na łóżku. = The phone is lying on the bed.

Yes, it is understandable, but leży sounds more natural in this context.

• jest obok butelki = is next to the bottle
• leży obok butelki = is lying next to the bottle

Using jest is more neutral and less descriptive. Using leży tells you something about the object's position. For a small object like a bottle cap, Polish speakers will very often use leży.

Nakrętka usually means a cap, screw cap, or lid that twists on.

In the context of a bottle, it is naturally understood as the bottle cap.

It is related to the verb nakręcać / nakręcić, meaning to screw on, wind, or twist on, so nakrętka often refers to something you screw onto something else.

Depending on context, English translations could include:

• cap
• screw cap
• sometimes lid

Because it is the subject of the sentence, and Polish commonly places the subject first.

So the basic structure is:

• Nakrętka = subject
• leży = verb
• obok butelki = location phrase

Polish word order is more flexible than English, though. You could also hear:

• Obok butelki leży nakrętka.

This would put more focus on the location first, a bit like:

• Next to the bottle, there is a cap lying.

Both are grammatical, but the original order is the most neutral.

A rough English-friendly guide is:

na-KRENT-ka LEH-zhih OH-bok boo-TEL-kee

A few important points:

• ę in nakrętka is a nasal vowel; before t, it is often pronounced something like en
• rz in leży sounds like the s in measure
• y in leży is not exactly like English ee; it is a shorter, more central vowel
• stress in Polish is usually on the second-to-last syllable:
  • naKRĘTka
  • LEży
  • Obok
  • buTELki

Yes, leży is 3rd person singular present tense.

The base form is leżeć = to lie.

Conjugation:

• ja leżę = I am lying
• ty leżysz = you are lying
• on / ona / ono leży = he / she / it is lying
• my leżymy
• wy leżycie
• oni / one leżą

In your sentence, nakrętka is singular, so leży is the correct form.

Yes, it matters.

Nakrętka is feminine, and one clue is that it ends in -a, which is very common for feminine nouns in Polish.

It matters because:

• adjectives would have to agree with it
• past tense verbs would show feminine agreement
• some pronouns referring to it would also reflect its gender

In the present-tense sentence Nakrętka leży obok butelki, the verb form leży does not visibly change for grammatical gender, but gender is still part of the noun's grammar.

For example:

• Mała nakrętka leży obok butelki. = The small cap is lying next to the bottle.

Here mała is feminine because nakrętka is feminine.

Yes. Polish does not have articles like a and the, so butelki could correspond to either:

• next to a bottle
• next to the bottle

The exact meaning depends on context.

The same is true for nakrętka:

• Nakrętka leży obok butelki could mean
  • The cap is lying next to the bottle
  • A cap is lying next to a bottle

In practice, context usually makes it clear.