Compound and Complex Sentences | Russian Grammar

Once you can build a single clause, the next step is joining clauses into longer thoughts. Russian does this two ways. A compound sentence links clauses of equal weight with a coordinator (и, а, но, и́ли) — neither clause depends on the other. A complex sentence attaches a subordinate clause to a main one with a subordinator (что, что́бы, когда́, потому́ что, е́сли, хотя́, кото́рый) — the subordinate clause can't stand alone. The grammar of the clauses themselves you already know; what's new is the joining — and above all the punctuation, because Russian commas obey a strict rule that English's looser comma habits will sabotage.

Compound sentences: coordination

Compound sentences glue two independent clauses with a coordinating conjunction. The big four:

Conjunction	Meaning	Use
и	and	adds, links similar ideas
а	and / but / whereas	contrast of two different things
но	but	direct contradiction / obstacle
и́ли	or	alternatives
одна́ко	however (formal)	elevated contrast

Я чита́л, и он писа́л.

I was reading, and he was writing. — two independent clauses joined by и; comma before и because there are two subjects/clauses.

Я хоте́л пойти́, но пошёл дождь.

I wanted to go, but it started raining. — но contrasts two clauses; comma before но.

The а / но distinction is worth pausing on, because English collapses both into "but." Но marks a genuine obstacle or contradiction (I wanted to, but it rained). А marks a simple contrast between two different situations — closer to "whereas" / "and on the other hand":

Я люблю́ чай, а она́ лю́бит ко́фе.

I like tea, and she likes coffee. — а: contrast of two parallel facts, not a contradiction. (но would wrongly suggest a conflict.)

Э́то не чай, а ко́фе.

This isn't tea, it's coffee. — а after a negation: 'not X but Y' is always а, never но.

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Russian almost always puts a comma before а and но — they join two clauses, and the clause boundary demands a comma. Before и the comma appears when и links two full clauses (each with its own subject), but is omitted when и just links two items in one clause: Я чита́л и писа́л (one subject, no comma) vs Я чита́л, и он писа́л (two clauses, comma).

Complex sentences: subordination

A complex sentence has a main clause plus a subordinate clause introduced by a subordinator. The subordinate clause depends on the main one and can't stand alone. The high-frequency subordinators:

Subordinator	Meaning
что	that (reporting a fact)
что́бы	so that / in order to (purpose, wish)
когда́	when
потому́ что	because
е́сли	if
хотя́	although
кото́рый	which / who / that (relative)

Я зна́ю, что он прав.

I know that he's right. — main clause + что-clause; comma before что.

Когда́ он пришёл, мы у́жинали.

When he arrived, we were having dinner. — subordinate clause first, then main; comma at the boundary between them.

Я не пошёл на рабо́ту, потому́ что заболе́л.

I didn't go to work because I got sick. — потому́ что introduces the reason; comma before потому́.

Note from когда́ он пришёл, мы у́жинали: when the subordinate clause comes first, the comma sits between the two clauses (after пришёл). Russian marks the boundary wherever it falls — front, middle, or end.

что vs что́бы

These two look almost identical but do opposite jobs. Что ("that") reports a fact with an indicative verb. Что́бы ("so that / in order to") expresses purpose or a wish, and forces the past-tense form of the verb after it (a subjunctive remnant):

Я ду́маю, что он прие́дет.

I think (that) he'll come. — что reports a belief; future verb прие́дет.

Я хочу́, что́бы он прие́хал.

I want him to come. — что́бы expresses a wish; the verb must be past-form прие́хал, not future.

The full mechanics of this pair — including why что́бы demands the past form, and how it differs from the English infinitive "to come" — are on что vs что́бы.

Relative clauses with кото́рый

The relative pronoun кото́рый ("which / who / that") attaches a whole clause to a noun. It agrees in gender and number with the noun it refers back to, but takes its case from its own role inside the relative clause:

Я зна́ю челове́ка, кото́рый живёт здесь.

I know the man who lives here. — кото́рый refers to челове́ка (masc.) but is nominative because it's the subject of 'lives'. Comma before кото́рый.

Кни́га, кото́рую ты дал мне, о́чень интере́сная.

The book you gave me is very interesting. — кото́рую: feminine (agrees with кни́га) + accusative (object of 'gave'). Commas around the inserted clause.

Crucially, English can drop the relative pronoun — "the book you gave me" — but Russian never drops кото́рый, and always sets the relative clause off with commas. The full agreement/case system is on relative clauses with кото́рый.

Building up: from two clauses to many

The skill is incremental. Start with one clause, add a coordinator for a second equal clause, then nest a subordinate clause:

Он позвони́л и сказа́л, что опозда́ет, потому́ что попа́л в про́бку.

He called and said he'd be late because he got stuck in traffic. — coordination (и) + что-clause + потому́ что-clause; a comma at every clause boundary.

Count the commas: one before что (start of the reported clause), one before потому́ что (start of the reason clause). The и links two verbs of the same subject (позвони́л и сказа́л), so no comma there. Every boundary between clauses is marked; every boundary inside one clause is not.

The distinguishing insight: the comma is mechanical, not stylistic

In English, commas before "that," "which," and "because" are optional, even discouraged — "I know that he's right" takes no comma. In Russian the comma at a clause boundary is grammatically obligatory, not a matter of taste. There is a clause boundary before что, что́бы, когда́, потому́ что, е́сли, хотя́, кото́рый, and around any embedded clause — so there is a comma, every time, no exceptions. Russians are taught these as fixed rules and notice their absence instantly. Treat the comma as part of the conjunction itself: learn ", что" and ", кото́рый" as units.

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A practical heuristic: if you can point to two verbs (two clauses), there's a comma between them. Я зна́ю, что он прав — two clauses (зна́ю + a что-clause whose predicate is прав) → comma. Я чита́л и писа́л — one subject, the и just links two activities, no second clause → no comma. Count the subject-predicate pairs; a comma marks the seam between each.

Common Mistakes

❌ Я зна́ю что он прав.

Wrong — Russian requires a comma before что at the clause boundary, unlike English.

✅ Я зна́ю, что он прав.

I know that he's right. — obligatory comma before что.

❌ Кни́га кото́рую ты дал мне о́чень интере́сная.

Wrong — the relative clause must be fenced with commas: before кото́рую and after мне.

✅ Кни́га, кото́рую ты дал мне, о́чень интере́сная.

The book you gave me is very interesting. — commas around the кото́рый-clause.

❌ Я люблю́ чай, но она́ лю́бит ко́фе.

Off — there's no contradiction here, just a contrast of two facts, so it should be а, not но.

✅ Я люблю́ чай, а она́ лю́бит ко́фе.

I like tea, and she likes coffee. — а for parallel contrast.

❌ Я хочу́ что он прие́дет.

Wrong twice — a wish needs что́бы (not что), and the verb must be past-form: прие́хал.

✅ Я хочу́, что́бы он прие́хал.

I want him to come. — что́бы + past-form verb + obligatory comma.

❌ Когда́ он пришёл мы у́жинали.

Wrong — when the subordinate clause comes first, the comma still marks the boundary, after пришёл.

✅ Когда́ он пришёл, мы у́жинали.

When he arrived, we were having dinner. — comma between the fronted clause and the main one.

Key Takeaways

Compound = equal clauses joined by coordinators (и, а, но, и́ли, одна́ко); complex = a subordinate clause attached by subordinators (что, что́бы, когда́, потому́ что, е́сли, хотя́, кото́рый).
а = parallel contrast / "whereas"; но = real contradiction / obstacle. After a negation, "not X but Y" is always а.
The comma at a clause boundary is obligatory — before что, что́бы, когда́, потому́ что, кото́рый, and around any embedded clause. This is the top error for English speakers.
и takes a comma only when it links two full clauses, not when it links two items in one clause.
кото́рый is never dropped and its clause is always set off with commas — unlike English, which omits both freely.

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