Стюардесса принесла воду моей соседке, потому что ей стало нехорошо.

Because it is past tense, singular, feminine.

The subject is стюардесса (flight attendant / stewardess), which is a feminine noun, so the verb in the past tense must also be feminine:

• он принёс = he brought
• она принесла = she brought
• они принесли = they brought

So стюардесса принесла means the stewardess brought.

Because воду is the accusative case, which is used for the direct object of the verb.

Here, the thing being brought is water, so вода changes to воду:

• вода = water (dictionary form, nominative)
• принести воду = to bring water

This is very common in Russian: the direct object often goes into the accusative.

Because this is the indirect object: the person to whom the water was brought.

Russian uses the dative case for that idea.

• моя соседка = my neighbor / my seatmate
• моей соседке = to my neighbor / to my seatmate

Both words change because the adjective/pronoun and the noun must agree:

• моя → моей
• соседка → соседке

So:

• принесла воду моей соседке = brought water to my neighbor

Literally, yes, соседка means female neighbor. But in context it can also mean the woman sitting next to me or my seatmate.

In a plane context, many learners expect a special word, but Russian often uses сосед / соседка in a broader sense for someone nearby, including a person next to you.

So here моей соседке most naturally means something like the woman sitting next to me.

Literally, it is something like:

• ей = to her
• стало = it became
• нехорошо = not well / unwell

So the whole expression means:

• she started to feel unwell
• she became unwell

This is a very common Russian pattern for physical or emotional states:

• мне стало плохо = I started feeling bad / sick
• ему стало холодно = he became cold
• ей стало грустно = she became sad

It is an impersonal construction, which is why it does not work like a normal English sentence with a clear subject + adjective.

Because Russian uses the dative case in this kind of impersonal expression.

With feelings or states that come over a person, Russian often says something like to her it became unwell, not she became unwell.

So:

• она = she
• ей = to her

You will often see this with words like:

• плохо = bad / sick
• нехорошо = unwell
• холодно = cold
• жарко = hot
• скучно = bored

Examples:

• Мне плохо. = I feel sick / bad.
• Ему стало страшно. = He became scared.

Grammatically, ей could in principle refer to either feminine person mentioned earlier:

• стюардесса
• соседка

But in normal interpretation, it most naturally refers to моей соседке, because the sentence says the stewardess brought water to the neighbor because she felt unwell. That is the most logical reading.

So this is a good example of how Russian pronouns, like English ones, can sometimes be technically ambiguous, but context usually makes the intended meaning clear.

Because стало is part of an impersonal construction.

In ей стало нехорошо, the verb does not agree with a nominative subject like она. Instead, Russian uses neuter singular стало in this set pattern.

Compare:

• Она стала грустной. = She became sad.
  This is a personal construction with она as the subject.

• Ей стало грустно. = She became sad / She started feeling sad.
  This is impersonal, with ей in the dative.

So стало is correct because the sentence is built impersonally.

Yes, плохо would also be possible, and it is very common:

• ей стало плохо = she felt sick / she became ill

Нехорошо is slightly softer and can sound a bit more polite or understated. In contexts like travel, public places, or formal speech, it can sound quite natural.

Very roughly:

• плохо = bad, sick, unwell
• нехорошо = not well, unwell

So the difference is mostly one of tone, not basic grammar.

Because потому что introduces a subordinate clause: because she felt unwell.

Russian normally puts a comma before subordinate conjunctions like:

• что = that
• когда = when
• если = if
• потому что = because

So:

• Стюардесса принесла воду моей соседке, потому что ей стало нехорошо.

That comma is standard Russian punctuation.

Yes. Russian word order is more flexible than English because case endings show the grammatical roles.

For example, these are all possible, though they may sound slightly different in emphasis:

• Стюардесса принесла воду моей соседке...
• Стюардесса моей соседке принесла воду...
• Воду моей соседке принесла стюардесса...

The basic meaning stays the same because:

• воду is accusative
• моей соседке is dative

But word order affects focus and style, so the original sentence is simply a neutral, natural version.

Принесла is perfective.

Its infinitive is принести = to bring (successfully, as a completed action).

That fits this sentence because it refers to a completed event: the stewardess actually brought the water.

Compare:

• приносила (imperfective) = was bringing / used to bring / brought in a more process-oriented sense
• принесла (perfective) = brought, completed the action

So принесла is the natural choice when telling what happened.

Because Russian simply does not have articles.

So стюардесса can mean:

• the stewardess
• a stewardess

and the listener figures it out from context.

The same is true for:

• воду = water / the water
• соседке = to a neighbor / to my neighbor, depending on context

In this sentence, моей already makes соседке specific: my neighbor / my seatmate.