В багажнике лежат зонт, аптечка и запасная бутылка воды.

В багажнике means in the trunk. Here в expresses location, so it takes the prepositional case.

• багажник = trunk / boot
• в багажнике = in the trunk

Compare:

• в багажник = into the trunk (accusative, movement)
• в багажнике = in the trunk (prepositional, location)

So the sentence is talking about where the items are, not where they are being put.

Because the subject is a list of several things:

• зонт = umbrella
• аптечка = first-aid kit
• запасная бутылка воды = spare bottle of water

Together, they form a plural subject, so the verb is plural:

• лежит = lies / is lying / is located there (singular)
• лежат = lie / are lying / are located there (plural)

So:

• В багажнике лежит зонт. = There is an umbrella in the trunk.
• В багажнике лежат зонт, аптечка и запасная бутылка воды. = There are an umbrella, a first-aid kit, and a spare bottle of water in the trunk.

Yes, literally лежат means are lying. But in Russian, verbs like лежать, стоять, and висеть are often used where English simply says there is/there are or is located.

So here лежат suggests that the items are resting in the trunk, not standing upright or hanging.

Common related verbs:

• лежать / лежат = lie / be lying
• стоять / стоят = stand / be standing
• висеть / висят = hang / be hanging

Russian often chooses a verb based on the physical position of the object.

In present-tense Russian, there is often no direct equivalent of English there is / there are in simple sentences like this.

Russian commonly expresses the idea with:

• location + verb of position

So instead of saying something exactly like There are X in the trunk, Russian naturally says something like:

• In the trunk lie X, Y, and Z.

You could also use other constructions, but лежат sounds very natural here.

Зонт is in the nominative singular because it is one of the things that лежат.

Its dictionary form is already зонт, so it looks unchanged.

The same is true for:

• аптечка — nominative singular
• бутылка — nominative singular

These are the items being listed as the subject of the sentence.

Because запасная describes бутылка, and бутылка is a feminine noun.

So the adjective must agree with the noun in:

• gender
• number
• case

Here:

• бутылка = feminine, singular, nominative
• therefore запасная = feminine, singular, nominative

Compare:

• запасной зонт = spare umbrella
• запасная аптечка = spare first-aid kit
• запасное колесо = spare wheel

Because after a container noun like бутылка (bottle), Russian usually puts the contents in the genitive case.

So:

• бутылка воды = a bottle of water

Here:

• вода is the dictionary form
• воды is the genitive singular

This is very common in Russian:

• чашка чая = a cup of tea
• стакан молока = a glass of milk
• бутылка воды = a bottle of water

In this sentence, yes, that is the most natural interpretation.

Багажник can mean:

• a car trunk / boot
• sometimes a luggage rack

But because the sentence says в багажнике (in the trunk), it strongly suggests the enclosed storage space of a car.

If it meant a luggage rack on top of a car or bicycle, you would more likely expect на багажнике (on the rack).

This is normal Russian word order. Russian often puts the location or setting first, especially when introducing what is found there.

So:

• В багажнике лежат зонт, аптечка и запасная бутылка воды.

feels natural as:

• As for the trunk, it contains...
• In the trunk, there are...

You could reorder it, for example:

• Зонт, аптечка и запасная бутылка воды лежат в багажнике.

That is also grammatical, but it sounds a bit more like you are emphasizing the items themselves rather than the location.

Not in this sentence.

Russian often omits the present tense of to be:

• Он врач. = He is a doctor.

But here the verb is not just to be. The sentence uses лежать (to lie / to be lying), which carries real meaning. So the verb should stay.

Without it, the sentence would sound incomplete or unnatural.

Because Russian punctuation works much like English for simple lists.

In a list of three items:

• items are separated by commas
• the final item is introduced by и = and

So:

• зонт, аптечка и запасная бутылка воды

This is the normal way to punctuate a list in Russian.

Yes. Depending on context, лежат could be translated as:

• are lying
• are in
• are located
• there are

In this sentence, natural English usually avoids the literal are lying unless you want to stress physical position. So a smoother translation is often something like:

• There are an umbrella, a first-aid kit, and a spare bottle of water in the trunk.

But grammatically, the Russian verb still literally means lie / are lying.

It can be either, depending on context.

Russian present tense here simply states the current situation:

• those items are in the trunk

That could mean:

• they are there right now
• they are normally kept there
• someone packed them there earlier

The sentence itself does not force one interpretation. Context decides.

For a learner, лежат is the correct and safest choice, because the sentence has a list of several items.

You may sometimes hear singular agreement with a following list in informal speech, especially when the speaker is presenting the items almost one by one, but that is not the neutral standard choice to imitate at first.

So for this sentence, use:

• В багажнике лежат зонт, аптечка и запасная бутылка воды.

not

• В багажнике лежит зонт, аптечка и запасная бутылка воды.

Because Russian has no articles.

So a noun like зонт can mean:

• an umbrella
• the umbrella

depending on context.

The same applies to the whole sentence: Russian does not explicitly mark a vs the the way English does. You infer that from the situation.

So:

• зонт could be an umbrella or the umbrella
• аптечка could be a first-aid kit or the first-aid kit

English has to choose; Russian usually does not.