In short

An adverbial participle (дієприслівник) is a verb form that adds a secondary action alongside the main verb, performed by the same subject. English uses “-ing” or “having done” for this: Reading the book, she took notes / Having finished, he left. Ukrainian has two forms:

• imperfective (-чи: чита́ючи “while reading”) for an action happening at the same time as the main verb;
• perfective (-вши/-ши: зроби́вши “having done”) for an action completed before the main verb.

The дієприслівник never changes for person, gender, or number, because it always borrows its subject from the main verb of the sentence.

The rule

One subject for both actions. The person doing the side action must be the same person doing the main action. Reading, she took notes works because she both reads and takes notes. If the two doers differ, you cannot use a дієприслівник; use a clause with коли / бо / після того як instead.

No subject at all still counts. In an impersonal sentence built on an infinitive — after ле́гко, ва́жко, тре́ба, мо́жна, дово́диться — the зворо́т is standard, because both actions belong to one implied doer: Чита́ючи шви́дко, ле́гко пропусти́ти дета́лі. What must match is the doer, stated or implied, not a nominative subject. Take the infinitive away and the implied doer goes with it: after Мені́ ста́ло су́мно the зворо́т is out.

Pick the form by timing:

• Same time as the main verb → imperfective, ending -чи. Build it from the third-person-plural present stem: чита́ють → чита́ючи.
• Finished before the main verb → perfective, ending -вши (after a vowel) or -ши (after a consonant). Build it from the infinitive/past stem: зроби́ти → зроби́вши.

Reflexive verbs keep the particle, which slides to the very end: усміха́тися → усміха́ючись; поверну́тися → поверну́вшись.

Punctuation: the whole дієприслівниковий зворот (the participle plus the words that depend on it) is fenced off by commas, wherever it sits.

Forms & patterns

Imperfective (-чи) — simultaneous action, from the «вони» present stem

Perfective (-вши / -ши) — action completed first, from the infinitive stem

Note the pattern: a stem ending in a vowel takes -вши (зроби́вши), a stem ending in a consonant takes -ши (прині́сши, прийшо́вши).

Examples

Common mistakes

• Читая книжку, вона… -> Читаючи книжку, вона… — the ending -я is Russian; the Ukrainian imperfective form ends in -чи.
• Читаючи книжку, задзвонив телефон. -> Читаючи книжку, я не почув дзвінка. — the side action and the main action need one shared subject; a phone cannot be reading.
• Зробив уроки, діти пішли гуляти. -> Зробивши уроки, діти пішли гуляти. — the first (prior) action must be the participle зробивши, not the finite past зробив.
• Роблячи уроки, діти пішли гуляти. -> Зробивши уроки, діти пішли гуляти. — a completed prior action needs the perfective -вши, not the imperfective -чи.
• Повернувши додому, я… -> Повернувшись додому, я… — the verb is reflexive, so the participle keeps -сь at the end (and повернувши alone would come from non-reflexive «повернути» = to turn/return something).
• Прийшовши додому він відпочив. -> Прийшовши додому, він відпочив. — the дієприслівниковий зворот is always set off by a comma.

Tips

• Two questions choose the form: same time? → imperfective -чи; finished first? → perfective -вши/-ши.
• Build the -чи form off the вони present, not the infinitive: пи́шуть → пи́шучи (not “писа́ючи”).
• Reflexive verbs keep the particle at the very end: -сь after -чи (усміха́ючись), -ся/-сь after -вши (поверну́вшись).
• The “one subject” test: could you rewrite it as “while X was doing… X did…”? If the two X’s differ, switch to a коли / бо clause; if there is no X at all, the test still passes when the predicate is an infinitive — one implied doer covers both actions.
• Negation is simply не in front: не зна́ючи, не поміча́ючи.
• «бути» is irregular — its adverbial participle is бу́дучи (“being”).
• These forms are common in writing and neutral speech; for casual speech many speakers prefer a plain clause (коли я прийшов…).