Preposition plus Infinitive | Farsi Grammar

The Persian infinitive can function as a verbal noun after a preposition: برای رفتن “in order to go/for going,” قبل از دیدن “before seeing,” بدون گفتن “without saying.” The infinitive retains verbal meaning and may take an object or directional phrase, but it carries no tense or person agreement.

English alternates among infinitives, gerunds, and finite clauses after prepositions. Persian organizes the contrast differently: a compact infinitive phrase normally leaves its subject to context, while اینکه + finite clause can make subject, tense, mood, or the scope of negation explicit.

The main patterns

Pattern	Relationship	Example phrase	Typical register
برای + infinitive	purpose	برای خریدن بلیت	neutral; sometimes heavier than a subjunctive purpose clause
قبل از / پیش از + infinitive	earlier event	قبل از بیرون رفتن	neutral / formal
بعد از / پس از + infinitive	later event	پس از رسیدن	neutral / formal
بدون + infinitive	absent accompanying action	بدون خداحافظی کردن	neutral
به جای + infinitive	substitute action	به جای منتظر ماندن	neutral

برای رفتن به فرودگاه تاکسی گرفتیم.

barâ-ye raftan be forudgâh tâksi gereftim.

We took a taxi to go to the airport. (neutral standard)

قبل از خوابیدن در ورودی را قفل کن.

qabl az khâbidan dar-e vorudi râ qofl kon.

Lock the entrance door before going to sleep. (neutral standard)

او بدون گفتن نشانی دقیق رفت.

u bedun-e goftan-e neshâni-ye daqiq raft.

He/She left without giving an exact address. (neutral standard)

به جای خریدن ماشین، دوچرخه‌اش را تعمیر کرد.

be jâ-ye kharidan-e mâshin, docharkhe-ash râ ta'mir kard.

Instead of buying a car, he/she repaired the bicycle. (neutral standard)

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Persian infinitives after prepositions are noun-like in syntax but verb-like in meaning. Keep the dictionary form in ـن and attach person and tense only in a finite alternative.

The understood subject is usually shared

When no subject appears inside the infinitive phrase, the listener normally identifies its actor with the most plausible participant in the main clause. In قبل از بیرون رفتن پنجره‌ها را بستم, “I” both closed the windows and went out.

قبل از بیرون رفتن همه‌ی چراغ‌ها را خاموش کردم.

qabl az birun raftan hame-ye cherâgh-hâ râ khâmush kardam.

Before going out, I turned off all the lights. (shared subject: I)

مریم بدون نگاه کردن به نقشه راه را پیدا کرد.

Maryam bedun-e negâh kardan be naqshe râh râ peydâ kard.

Maryam found the way without looking at the map. (shared subject: Maryam)

به جای منتظر ماندن، خودم به شرکت زنگ زدم.

be jâ-ye montazer mândan, khod-am be sherkat zang zadam.

Instead of waiting, I called the company myself. (shared subject: I)

This interpretation is a discourse inference, not person marking on رفتن، نگاه کردن, or منتظر ماندن. The infinitive has the same form regardless of who performs the action.

Objects and other complements remain inside

An infinitive can retain the argument structure of its verb. نگاه کردن still selects به, رفتن can retain a goal, and a transitive infinitive can have an object. The preposition outside the infinitive scopes over the whole event phrase.

پیش از دیدن فیلم نقد‌هایش را نخوان.

pish az didan-e film naqd-hâ-yash râ na-khân.

Don't read its reviews before seeing the film. (neutral standard)

بدون گفتن حقیقت نمی‌توانیم مشکل را حل کنیم.

bedun-e goftan-e haqiqat nemi-tavânim moshkel râ hal konim.

We cannot solve the problem without telling the truth. (neutral standard)

The apparent -e after دیدن and گفتن is ezâfe, reflecting the infinitive's nominal side: didan-e film, goftan-e haqiqat. Semantically, فیلم is what is seen and حقیقت what is said. More elaborate object marking with را is possible in nominalized clauses, but these compact compounds are the normal forms here.

For the noun-like behavior of these forms, see Nominalized Infinitives.

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Preserve the inner verb frame. The outer structure is بدون [event]; inside it, the predicate still determines whether a following participant uses ezâfe, به, از, or another marker.

Naming a different participant

An infinitive phrase can package an event with an overt participant through a nominal relationship: پس از رسیدن قطار “after the train's arrival,” پیش از آمدن مهمان‌ها “before the guests' arrival.” This compact structure is common in formal and written Persian.

پس از رسیدن قطار، مسافران به سوی خروجی رفتند.

pas az residan-e qatâr, mosâferân be su-ye khoruji raftand.

After the train arrived, the passengers headed toward the exit. (formal-neutral)

پیش از آمدن مهمان‌ها، اتاق را مرتب کردیم.

pish az âmadan-e mehmân-hâ, otâq râ morattab kardim.

Before the guests arrived, we tidied the room. (neutral standard)

These examples do not have a shared actor: the train arrives but the passengers move; the guests arrive but “we” tidy. The explicit participant makes the event nominal and resolves reference.

When a finite clause is clearer

Use اینکه + finite clause when the subordinate event needs an explicit subject or finite tense or mood; it can also disambiguate whose action falls under negation. This alternative is generally more transparent in conversation and avoids ambiguity about the infinitive's understood actor.

پیش از اینکه قطار برسد، از خط زرد فاصله بگیرید.

pish az inke qatâr be-resad, az khatt-e zard fâsele be-girid.

Before the train arrives, stand back from the yellow line. (formal announcement)

بدون اینکه کسی متوجه شود، پرونده را از اتاق بیرون برد.

bedun-e inke kasi motavajjeh shavad, parvande râ az otâq birun bord.

He/She took the file out of the room without anyone noticing. (neutral standard)

برای اینکه دیر نرسیم، یک ساعت زودتر راه افتادیم.

barâ-ye inke dir na-resim, yek sâ'at zud-tar râh oftâdim.

So that we would not arrive late, we set off an hour earlier. (neutral standard)

The infinitive alternative برای دیر نرسیدن is grammatical, but the finite clause more directly expresses the intended subject “we.” Choice is therefore partly about information packaging, not correctness alone.

Register and style

Compact event nouns with پس از، پیش از, and long nominal chains are frequent in (formal) and (academic) prose. Everyday conversation favors بعد از، قبل از and finite clauses when the participants differ. بدون + infinitive and به جای + infinitive are natural in every register.

Do not confuse the Persian infinitive with English “to + verb.” The به in English to leave has no Persian counterpart; رفتن alone is the dictionary form. Persian برای رفتن includes a genuine purpose preposition.

Common Mistakes

1. Putting a finite verb directly after a preposition

❌ قبل از دیدم او، تماس گرفتم.

Incorrect — after قبل از, use the infinitive دیدن or a finite اینکه clause.

✅ قبل از دیدن او تماس گرفتم.

qabl az didan-e u tamâs gereftam.

I called before seeing him/her.

2. Copying English infinitival “to”

❌ برای به رفتن به فرودگاه تاکسی گرفتیم.

Incorrect — Persian infinitive رفتن does not contain a separate infinitival به.

✅ برای رفتن به فرودگاه اتوبوس گرفتیم.

barâ-ye raftan be forudgâh otobus gereftim.

We took a bus to go to the airport.

3. Dropping a preposition selected inside the infinitive phrase

❌ بعد از رسیدن خانه تماس گرفتم.

Incorrect — رسیدن retains its goal preposition به inside the larger temporal phrase.

✅ بعد از رسیدن به خانه تماس گرفتم.

ba'd az residan be khâne tamâs gereftam.

I called after arriving home.

4. Forcing a separate subject into a bare infinitive phrase

❌ بدون او چیزی گفتن، رفتیم.

Incorrect for ‘without him/her saying anything’ — use a finite اینکه clause to express the separate subject clearly.

✅ بدون اینکه او چیزی بگوید، رفتیم.

bedun-e inke u chizi be-guyad, raftim.

We left without him/her saying anything.

Key Takeaways

After a preposition, the Persian infinitive behaves as a verbal noun and has no person or tense marking.
With no expressed subject, the infinitive's actor is normally inferred from the main clause.
An overt participant can form a nominal event: پس از رسیدن قطار.
Use اینکه + finite clause when a separate subject, tense, negation, or mood must be explicit.
Preserve the inner predicate's complements, and do not add an English-style infinitival به.

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