Learn Hardcore Russian: Путешественница сидит у костра и рассказывает интересную историю. - The female traveler is sitting by the campfire and telling an interesting story.

Feminine agreement: эта путешественница, интересная путешественница, etc.
Feminine verb forms in the past: путешественница рассказывала, not рассказывал.

Why is it сидит, not сидитЬ or something else?

Сидеть is the infinitive: to sit.
Сидит is the 3rd person singular, present tense: (he/she) sits / is sitting.

Conjugation pattern (present tense):

я сижу – I sit / am sitting
ты сидишь – you sit / are sitting
он/она сидит – he/she sits / is sitting
мы сидим – we sit / are sitting
вы сидите – you sit / are sitting
они сидят – they sit / are sitting

In the sentence, the subject is путешественница (she), so we use сидит.

Why does у take костра and not костёр?

The preposition у (by, at, near) requires the genitive case.

Nominative (dictionary form): костёр (a campfire, bonfire)
Genitive singular: костра

So:

у костра = by/near the fire
нет костра = there is no fire (also genitive)

That’s why the sentence uses костра, not костёр.

What’s the difference between у костра and возле костра?

Both mean roughly “by the fire / near the fire.”

у костра – very common, neutral “at/by the fire.”
возле костра – also “near the fire,” sometimes with a slightly clearer sense of next to, close to.

In this sentence, у костра is completely natural; возле костра would also be acceptable with almost the same meaning.

Why is it рассказывает, not рассказываеть or рассказать?

Рассказывать is the infinitive: to tell / to narrate (imperfective).
Рассказывает is the 3rd person singular, present tense: (he/she) tells / is telling.

Conjugation (present):

я рассказываю
ты рассказываешь
он/она рассказывает
мы рассказываем
вы рассказываете
они рассказывают

Рассказать is a different verb: it’s the perfective partner, meaning to tell (to finish telling). You would use расскажет for “she will tell (once, to completion).”

Why is рассказывает (imperfective) used here, and not the perfective расскажет?

The imperfective aspect (рассказывать) focuses on:

an ongoing process
a repeated or descriptive action

The sentence describes what she is doing right now (sitting and telling a story), so the ongoing, descriptive aspect fits: рассказывает.

The perfective расскажет would suggest something like “she will tell (and finish telling) an interesting story,” focusing on completion, often in the future or as a single, whole event.

Why does интересную историю look different from the dictionary forms интересный and история?

Dictionary forms:

интересный – interesting (masculine, nominative)
история – story (feminine, nominative)

In the sentence, историю is the direct object of рассказывает (she tells what? – a story). Direct objects usually take the accusative case.

For a feminine noun ending in -я:

Nominative: история
Accusative: историю

The adjective must agree in gender, number, and case with the noun:

Feminine, singular, accusative: интересную

So we get: интересную историю (an interesting story).

Could we say just рассказывает историю without интересную?

Yes.
Путешественница сидит у костра и рассказывает историю.
This simply removes the detail that the story is interesting.

Adding интересную gives us more information about the quality of the story, but grammatically it’s optional.

Why isn’t она (she) written before сидит or рассказывает?

Russian often omits personal pronouns (я, ты, он, она, etc.) when the subject is clear from the context and verb endings.

Here, the subject путешественница is stated once. Both verbs сидит and рассказывает clearly refer to this feminine singular subject. There is no need to repeat она.

You could say:

Она сидит у костра и рассказывает интересную историю.

That is grammatically correct but slightly more redundant, unless you specifically want to emphasize она.

Why is there only one subject (путешественница) but two verbs?

In Russian (as in English), if two actions have the same subject, you usually mention the subject once and then connect the verbs with и (and):

Путешественница сидит у костра и рассказывает историю.
The traveler sits by the fire and tells a story.

Both verbs share the same subject путешественница, so you don’t repeat the noun.

Does сидит mean “sits” or “is sitting”? How do you say the English continuous form in Russian?

Russian does not have a separate continuous tense like English.
The simple present in Russian can mean both:

сидит = “she sits” (in general)
сидит = “she is sitting” (right now)

Context decides the meaning.
In this sentence, with a concrete scene (by the fire, telling a story), it naturally reads as “is sitting” and “is telling”.

Can the word order be changed, like У костра сидит путешественница и рассказывает интересную историю?

Yes. Russian word order is more flexible than English.

Путешественница сидит у костра и рассказывает интересную историю.
– More neutral: first identify who, then say what she’s doing and where.
У костра сидит путешественница и рассказывает интересную историю.
– Slightly emphasizes the location first: By the fire sits a traveler and is telling an interesting story.

Both are grammatically correct; the nuance of emphasis shifts slightly, but the basic meaning stays the same.