A subordinating conjunction does what a coordinating one does not: it makes one clause depend on another, marking it as the background when or the reason why. This page covers the two most common families — time subordinators (коли́ "when," по́ки "while," як ті́льки "as soon as") and cause subordinators (бо and тому́ що "because," оскі́льки "since"). Three things matter throughout: every subordinator takes an obligatory comma before it (this is a hard rule, not a stylistic choice); after коли́ referring to the future, Ukrainian puts the verb in the future tense where English uses the present; and бо, the everyday "because," can never start a sentence.
Time subordinators
These attach a clause that answers коли́? ("when?"). The clause can come first or second; when it comes first, a comma still separates the two clauses.
| Conjunction | Meaning |
|---|---|
| коли́ | when |
| по́ки | while; until (with negation) |
| до́ки | until, as long as |
| як ті́льки | as soon as |
| пі́сля то́го як | after |
| перш ніж / пе́ред тим як | before |
| відто́ді як / відко́ли | (ever) since |
Коли́ я був мали́й, ми жи́ли бі́ля мо́ря.
When I was little, we lived by the sea.
Як ті́льки дізна́єшся щось, одра́зу напиши́ мені́.
As soon as you find out anything, write to me right away.
Поми́й по́суд, пе́ред тим як ля́гти спа́ти.
Wash the dishes before going to bed.
A note on по́ки: with a non-negated verb it means "while" (По́ки ти спав, я все прибра́в — "While you slept, I tidied everything"); with a negated verb it means "until" (Поче́кай, по́ки не зателефону́ю — "Wait until I call"). The "until" sense carries a не that does not make the clause negative in meaning — it is an idiomatic "expletive" не that Ukrainian (like several Slavic languages) attaches to "until" clauses.
Не вихо́дь, по́ки не скі́нчиться дощ.
Don't go out until the rain stops.
After коли́ for the future: use the future tense
Here is the rule that catches every English speaker. In English, after "when / as soon as / until" pointing at the future, we use the present tense: "When I finish, I'll rest." Ukrainian is more logical — if the action is in the future, the verb is in the future tense, in both clauses:
Коли́ закі́нчу робо́ту, відпочи́ну.
When I finish work, I'll rest.
Як ті́льки приї́деш, подзвони́ мені́.
As soon as you arrive, call me.
Word for word the first is "When I will-finish work, I will-rest" — закі́нчу and відпочи́ну are both future. English forbids "when I will finish"; Ukrainian requires it. This is purely about the time the action belongs to: a future event gets the future tense regardless of the conjunction. The mechanics of the synthetic and analytic future are on the future tense overview and the future usage page.
Cause subordinators
These answer чому́? ("why?"). Ukrainian has several, sliding from the everyday бо up to the more formal connectives.
| Conjunction | Meaning | Register |
|---|---|---|
| бо | because | everyday, neutral |
| тому́ що | because | neutral / slightly more formal |
| оскі́льки | since, as, given that | formal / written |
| че́рез те що | because of the fact that | formal |
| завдяки́ тому́ що | thanks to the fact that | formal (positive cause) |
| зважа́ючи на те що | given that, considering that | formal / written |
Я не прийшо́в, бо захворі́в.
I didn't come because I got sick.
Ми взяли́ парасо́льки, тому́ що сино́птики обіця́ли дощ.
We took umbrellas because the forecasters promised rain.
Оскі́льки всі вже зі́бралися, мо́жемо почина́ти.
Since everyone has gathered, we can begin.
бо can never start a sentence
The most useful practical rule about cause: бо is the warm, everyday "because," but it is positionally restricted — it can only link a reason clause onto a preceding main clause. It can never open a sentence or stand as the first word of an answer. So you cannot answer "Why?" with "Бо I was tired" as a standalone sentence-starter in writing the way English allows "Because I was tired."
Він спі́знився, бо проспа́в.
He was late because he overslept.
If you need a reason clause at the front of a sentence, use тому́ що, оскі́льки, or че́рез те що, which can lead:
Тому́ що йшов дощ, ми лиши́лися вдо́ма.
Because it was raining, we stayed home.
Оскі́льки квитки́ скінчи́лися, ми пішли́ додо́му.
Since the tickets had sold out, we went home.
тому́ alone = "therefore" (the result, not the cause)
Keep тому́ що (because) apart from bare тому́ (therefore). They point in opposite directions: тому́ що introduces the cause, тому́ introduces the result/consequence. The same two facts, flipped:
Я не пішо́в, тому́ що було́ пі́зно.
I didn't go because it was late. (тому́ що → cause)
Було́ пі́зно, тому́ я не пішо́в.
It was late, therefore I didn't go. (тому́ → result)
The related result connective так що ("so / and so") works the same way — it introduces the consequence: Ми запізни́лися, так що дове́лося бра́ти таксі́ ("We were late, so we had to take a taxi").
The comma is obligatory before every subordinator
Unlike English, where the comma before "because / when / while" is often optional and style-dependent, Ukrainian punctuation is mandatory: a subordinate clause is always separated from the main clause by a comma, placed before the subordinating conjunction. There is no "and so I dropped the comma" leeway.
Подзвони́ мені́, коли́ дої́деш.
Call me when you get there.
Я залиши́вся вдо́ма, бо почува́вся пога́но.
I stayed home because I felt unwell.
When the subordinate clause comes first, the comma sits between the two clauses (after the subordinate clause): Коли́ дої́деш, подзвони́ мені́. When the subordinator is a multi-word phrase (пі́сля то́го як, перш ніж, тому́ що), the comma goes before the whole phrase, not inside it: ..., пі́сля то́го як ... — comma before пі́сля. The full punctuation system is on the punctuation page.
Source-language comparison
For an English speaker, two habits need rewiring. First, the future after коли́: "I'll call when I arrive" is Подзвоню́, коли́ приї́ду — both future, where English keeps "arrive" in the present. Treat the conjunction as irrelevant to the tense and ask only "is the action future?" Second, the mandatory comma before every subordinator: English lets you write "I stayed home because it rained" with no comma, but Ukrainian requires ..., бо... every time. And learn that бо cannot start a sentence — for a fronted reason, use тому́ що or оскі́льки.
For a learner from Russian, the structures match (когда → коли́, потому что → тому́ що, поэтому → тому́, пока → по́ки), and the future-after-when rule is shared, so the syntax transfers. The lexical retuning: the everyday "because" is бо (Ukrainian's high-frequency word, with no direct one-word Russian equivalent), "since/as" is оскі́льки, "therefore" is тому́ (not the Russian поэтому), and "as soon as" is як ті́льки.
Common Mistakes
❌ Коли́ закі́нчую робо́ту, відпочи́ну. (meaning: future)
Incorrect — a future action after коли́ takes the future tense, not the present: Коли́ закі́нчу робо́ту, відпочи́ну.
✅ Коли́ закі́нчу робо́ту, відпочи́ну.
When I finish work, I'll rest — future in both clauses.
❌ Бо я був уто́млений, я ліг ра́но.
бо cannot start a sentence — front the reason with тому́ що or оскі́льки: Оскі́льки я був уто́млений, я ліг ра́но.
✅ Я ліг ра́но, бо був уто́млений.
I went to bed early because I was tired — бо trails the main clause.
❌ Я залиши́вся вдо́ма бо йшов дощ.
Missing the obligatory comma before the subordinator: Я залиши́вся вдо́ма, бо йшов дощ.
✅ Я залиши́вся вдо́ма, бо йшов дощ.
I stayed home because it was raining — comma before бо.
❌ Було́ пі́зно, тому́ що я не пішо́в. (meaning: therefore)
Wrong connective — for 'therefore' use bare тому́, not тому́ що (which means 'because'): Було́ пі́зно, тому́ я не пішо́в.
✅ Було́ пі́зно, тому́ я не пішо́в.
It was late, therefore I didn't go — тому́ = result.
❌ Поче́кай, по́ки я зателефону́ю. (meaning: until I call)
The 'until' sense of по́ки idiomatically takes не: Поче́кай, по́ки я не зателефону́ю.
✅ Поче́кай, по́ки я не зателефону́ю.
Wait until I call — по́ки … не for 'until'.
Key Takeaways
- Time subordinators: коли́ "when," по́ки/до́ки "while/until," як ті́льки "as soon as," пі́сля то́го як "after," перш ніж / пе́ред тим як "before," відто́ді як / відко́ли "since."
- After коли́ / як ті́льки for a future event, use the future tense in both clauses — not the present as in English.
- по́ки … не = "until"; the не is idiomatic and does not negate the clause's meaning.
- Cause: бо (everyday, never starts a sentence), тому́ що (neutral/formal), оскі́льки "since," че́рез те що, завдяки́ тому́ що "thanks to."
- Keep тому́ що (because, the cause) apart from bare тому́ (therefore, the result).
- A comma before the subordinator is obligatory, every time.
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- Coordinating Conjunctions (І/Й, А, Але, Та)A1 — Joining equals: і/й 'and' (й after a vowel for euphony), та 'and' (bookish), and the three-way split English collapses — і/й pure addition, а 'and/but' for CONTRAST without conflict (Я тут, а він там; не…, а…), and але́ 'but' for genuine opposition (Хо́чу, але́ не мо́жу). Also про́те/одна́к 'however', або́/чи 'or', ні…ні 'neither…nor' (with double negation). The hardest pair is а vs але́. Comma rules: comma before а and але́, but not before a single connecting і.
- Subordinating Conjunctions: Condition, Purpose, ConcessionB1 — Three families of subordinators that English collapses or marks only with verb forms. CONDITION: якщо́ 'if' for real/likely conditions (with the FUTURE — Якщо́ бу́де дощ, залиши́мося вдо́ма) versus якби́ 'if' for hypotheticals (with PAST + би/б — Якби́ був дощ, ми б залиши́лися). PURPOSE: щоб 'so that / in order to', + infinitive for the same subject, + past form for a different subject; also для то́го щоб, аби́. CONCESSION: хоч/хоча́ 'although', незважа́ючи на те що 'despite', дарма́ що, хай/нехай 'even if'. Comma before the subordinator.
- The Future Tense: Three RoutesA2 — Ukrainian builds the future three ways. (1) The PERFECTIVE simple future — a perfective verb's present-shaped form IS its future: прочита́ю 'I'll read it through', напишу́, зроблю́, куплю́ — one word, a single result. (2) The IMPERFECTIVE analytic future — бу́ду + an imperfective infinitive (бу́ду чита́ти), the auxiliary бу́ду/бу́деш/бу́де/бу́демо/бу́дете/бу́дуть conjugating. (3) The IMPERFECTIVE synthetic future — the infinitive fused with the enclitic -му/-меш/-ме/-мемо/-мете/-муть (чита́тиму), a one-word imperfective future that Ukrainian has and Russian lacks. So 'I will read' is прочита́ю (finish it) OR бу́ду чита́ти OR чита́тиму (ongoing); the last two are interchangeable.
- Using the Future (and Present-for-Future)B1 — When to use each future and where Ukrainian and English diverge. Perfective simple future for a single completed future result (Я зроблю́ це за́втра, Він при́йде о шо́стій). Imperfective future (бу́ду чита́ти / чита́тиму) for ongoing or repeated future action. The PRESENT-for-future with motion verbs and timetables (За́втра ї́ду до Ки́єва, По́їзд відхо́дить о п’я́тій). And the big divergence: after коли́ 'when' and якщо́ 'if' pointing to the future, Ukrainian uses the FUTURE — Коли́ при́йдеш, подзвони́ — where English keeps the present ('when you arrive').
- Ukrainian Punctuation and Quotation MarksB1 — The punctuation conventions that differ from English: guillemets « » for quotes, the dash for dialogue, the dash that replaces a missing 'is', the obligatory comma before що / який / щоб / бо / коли, the decimal comma, and the lowercase months, days, and nationalities.
- Word Order: Free but Not RandomA1 — Ukrainian word order is flexible because case endings (not position) mark grammatical roles — but the freedom is pragmatic: the neutral order is Subject–Verb–Object, and you front the known topic and end with the new, emphasized information.