Я воспользуюсь скидкой при покупке костюма.

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Breakdown of Я воспользуюсь скидкой при покупке костюма.

• скидка: the discount
• покупка: the purchase
• костюм: the suit

Questions & Answers about Я воспользуюсь скидкой при покупке костюма.

Why is the verb воспользуюсь in the perfective aspect rather than an imperfective form like “буду пользоваться”?

Russian distinguishes between single, completed actions (perfective) and ongoing/repeated actions (imperfective). воспользоваться is the perfective counterpart of пользоваться. Saying Я воспользуюсь скидкой means “I will take advantage of the discount” as a one-time, complete event. If you said Я буду пользоваться скидкой, it would imply you plan to use that discount repeatedly or over some period of time.

Why is скидкой in the instrumental case, not accusative?

The verb воспользоваться governs the instrumental case. In Russian, verbs like воспользоваться answer the question “чем?” (with what?), so their objects go in the instrumental. Hence скидка → скидкой.

What role does the preposition при play before покупке, and why is покупке in the prepositional case?

The preposition при means “upon,” “at the time of,” or “in the event of” and always takes the prepositional (locative) case. It adds the nuance “when doing X.” So при покупке literally means “when buying.” You form it by putting покупка (a feminine noun) into the prepositional case: покупка → покупке.

Why is костюма in the genitive case?