Learn Hardcore Russian: Внезапно погас фонарь во дворе. - Suddenly the streetlight in the yard went out.

So the most literal order in English would be: “Suddenly went out the lantern in the yard.”
Natural English: “Suddenly, the lantern in the yard went out.”

What form is погас? Is it a tense? What is the infinitive?

Погас is:

past tense
masculine singular
perfective aspect

The infinitive is погаснуть – to go out, to go dark (completely).

Verb pair:

гаснуть – imperfective: to be going out, to be fading
погаснуть – perfective: to go out (as a completed event)

In this sentence, погас describes a completed event: the light went out at a specific moment.

Why is there no pronoun like он for фонарь? In English we would say “it went out.”

In Russian, you normally don’t use a pronoun when the subject is a noun that’s already in the sentence.

Погас фонарь. – The lantern went out.
(literally: went-out lantern)

Adding он would sound odd here:
✗ Он погас фонарь. – That actually means He extinguished the lantern (different structure and meaning).

Russian can put the verb first and the noun after it, and that is still a normal subject–verb relationship, without он / оно.

Why is the word order Внезапно погас фонарь во дворе and not Фонарь внезапно погас во дворе?

Both orders are grammatically correct:

Внезапно погас фонарь во дворе.
Puts more emphasis on suddenly and on the event of going out.
Фонарь внезапно погас во дворе.
Feels a bit more neutral or slightly more about the lantern as the topic.

Russian word order is flexible. Here:

Внезапно at the beginning highlights the suddenness.
Verb‑first (погас фонарь) can make the action/events feel a bit more vivid or “narrative,” as if you’re telling a story and something suddenly happens.

What is the difference between внезапно and вдруг? Could we say Вдруг погас фонарь во дворе?

Yes, you can say:

Вдруг погас фонарь во дворе.

Both внезапно and вдруг mean “suddenly.” Nuances:

вдруг – more colloquial, very common in speech and narrative; often used to introduce unexpected events.
внезапно – a bit more formal or bookish; slightly more “neutral” stylistically.

In most everyday contexts here, they are interchangeable with only a stylistic difference:

Вдруг погас фонарь во дворе. – sounds very natural in storytelling.
Внезапно погас фонарь во дворе. – a touch more literary/formal.

Why is the verb погас and not something like погасил?

Because погас is intransitive – the lantern itself went out.

погаснуть / погас – to go out (about a light, fire, etc.)
гасить / погасить – to extinguish (something)

Compare:

Погас фонарь. – The lantern went out. (no agent mentioned)
Он погасил фонарь. – He extinguished the lantern. (someone caused it)

So погас correctly describes a light going out on its own (or without saying who caused it).

What case is во дворе, and why is the preposition во instead of в?

Во дворе is:

preposition во (variant of в)
noun двор in prepositional case: двор → дворе

Meaning: “in the yard / in the courtyard.”

The form во is used instead of в to make pronunciation easier:

в дворе would have вд together, which is hard to pronounce.
In such cases, Russian often uses во before words starting with some consonant clusters (д, ф, etc.):
- во дворе – in the yard
- во Франции – in France

So во дворе is just the normal, euphonic form of в дворе.

What is the difference between двор and во дворе?

двор – the base noun, nominative case: yard, courtyard
во дворе – prepositional case with во, meaning in the yard / in the courtyard

Examples:

Двор пустой. – The yard is empty. (subject, nominative)
Дети играют во дворе. – Children are playing in the yard. (location, prepositional)

In your sentence, во дворе tells us where the lantern is / where it went out.

How do you know that фонарь is masculine, and how does that affect погас?

The noun фонарь ends in a soft sign ь, and such nouns can be masculine or feminine. You have to learn the gender with the word:

фонарь – masculine noun (a lantern / streetlight)

The past tense verb must match the subject’s gender and number:

masculine singular: погас
feminine singular: погасла
neuter singular: погасло
plural: погасли

So:

Погас фонарь. – The (masc.) lantern went out.
Погасла лампа. – The (fem.) lamp went out.

Can I say Фонарь во дворе внезапно погас? Does it change the meaning?

Yes, you can say:

Фонарь во дворе внезапно погас.

Meaning stays basically the same. Nuance:

Фонарь во дворе внезапно погас. – begins with фонарь во дворе, so the topic is clearly “the lantern in the yard”; then you add new information “suddenly went out.”
Внезапно погас фонарь во дворе. – starts with “suddenly went out,” so it feels more like telling a sudden event in a story.

Semantics are the same; it’s mostly about what you foreground (topic vs. event).

Why is погас perfective? Could we use the imperfective гас here?

Perfective погас is used because the action is a single, completed event: the light went out at one moment.

погас – went out (completely, at a point in time)
гас (past imperfective) – was going out / used to go out or describes the process, not the single result.

Possible use of imperfective:

Фонарь медленно гас. – The lantern was slowly going out / fading.

In your sentence, the adverb внезапно suggests a sharp, completed event, so погас (perfective) is the natural choice.

How do you pronounce these words correctly?

Approximate pronunciation with stressed syllables in CAPS:

внезапно – vnyE-zap-na → [v-nye-ZAP-na]
погас – pa-GAS → [pa-GAS]
фонарь – fa-NAR’ → [fa-NAR’] (final рь is soft)
дворе – dva-RYE → [dva-RYE]

Full sentence:
Внезапно погас фонарь во дворе.
[v-nye-ZAP-na pa-GAS fa-NAR’ va-dva-RYE]

(Real connected speech will blur some consonants, but this gives you the stress and basic sounds.)