Learn Hardcore Russian: Лампа горит ярко, когда я читаю книгу ночью. - The lamp shines brightly when I read a book at night.

The verb горит comes from гореть, literally “to burn.” When you say Лампа горит, you mean “the lamp is lit” or “the lamp’s bulb is on.”
By contrast, светить means “to shine” or “to give off light.” Both are possible with лампа:
• Лампа горит focuses on the lamp being switched on (the filament burning).
• Лампа светит highlights the act of emitting light.
Native speakers often use гореть for lamps, candles, fires, etc., and светить for any object that radiates light.

Why is ярко used here, and how is it formed?

Ярко is an adverb meaning “brightly.” It’s formed from the adjective яркий (“bright”) by replacing -ий with the adverbial suffix -о.
Position-wise, Russian adverbs of manner usually follow the verb: горит ярко. You could also say ярко горит, but the first version is more neutral.

Why is книгу in the accusative case?

The verb читать (“to read”) requires a direct object in the accusative case.
• Книга is nominative (the subject).
• Книгу is accusative (the thing you’re reading).
So я читаю книгу = “I am reading a book.”

Why is there no preposition before ночью?

Ночью is an adverbial noun in the instrumental case used without a preposition to express “at night.” Other examples: утром (in the morning), днём (in the daytime), вечером (in the evening). It simply tells you when something happens.

Why is the comma placed before когда, and how does когда function?

Когда means “when” and introduces a subordinate clause of time. In Russian, you place a comma before a subordinate clause regardless of whether it comes before or after the main clause. Here the main clause is Лампа горит ярко, and the subordinate clause is когда я читаю книгу ночью.

Why is читаю in the present tense? Isn’t English using “I am reading”?

Russian doesn’t have a separate progressive aspect. The present tense in Russian covers both simple present (“I read regularly”) and present continuous (“I am reading right now”). Context tells you whether it’s a habitual action or something happening at the moment. Here it could be either “when I read at night (habitually)” or “when I’m reading a book tonight.”

Can I omit the pronoun я in когда я читаю книгу ночью?

Yes. Russian is a pro-drop language, so you can say когда читаю книгу ночью and it’s still clear you mean “I.” Including я adds emphasis or clarity but isn’t required grammatically.

Can I put the time clause first? For example, Когда я читаю книгу ночью, лампа горит ярко?

Absolutely. Russian allows you to start with the subordinate clause. You must keep the comma, though. Both word orders are correct; the difference is just rhythm or emphasis.