Questions & Answers about Я закрою окно прежде чем пойду спать.
Why is закрою in the perfective future rather than an imperfective or present form?
Закрою is the future form of the perfective verb закрыть, which highlights a single, completed action. In Russian, perfective verbs express the action’s completion and require a future form when you talk about an event that hasn’t happened yet. An imperfective form like закрываю would either sound like a present continuous (“I am closing”) or, in a compound future (буду закрывать), convey repetition or duration (“I will be closing [habitually or for a while]”), which doesn’t fit here.
Why is пойду used instead of an imperfective future like буду идти or a present?
Пойду is the perfective future of идти used with an infinitive (спать) to mean “go to sleep.” It marks a one-off action that will be carried out and completed. Imperfective буду идти would emphasize the process or duration (“I will be going”), and present иду would place the action in the present moment, neither of which match the intended meaning “I will go to sleep later.”
Why do we use the conjunction прежде чем and not just прежде or another preposition?
Прежде чем is the standard subordinating conjunction for “before” when linking two clauses. Прежде alone is an adverb meaning “earlier” or “formerly” and cannot connect clauses. You could alternatively use до того как, which is slightly more formal but synonymous:
• “Я закрою окно, до того как пойду спать.”