Learn Hardcore Russian: Перед уходом я закрываю окно.

The preposition перед requires the instrumental case (it answers “before what?”), so the noun уход becomes уходом. Russian expresses “before leaving” with a noun-phrase in instrumental instead of a gerund.

Why is the verb закрываю in the imperfective present tense? Shouldn’t it be perfective or future?

Imperfective verbs describe ongoing or habitual actions. Here закрываю implies a routine (“I always close the window before I leave”). If you want to talk about a single completed action in the future, you’d use the perfective future: Перед уходом я закрою окно.

Why is the personal pronoun я included? Can it be dropped?

Verb endings already show the subject, so я is optional. You can say Перед уходом закрываю окно with no change in meaning. Including я adds emphasis or clarity about who is doing it.

Why is окно in the accusative case and why is there no preposition before it?

The verb закрывать is transitive and takes a direct object in the accusative case without a preposition. Since окно is neuter singular, its accusative form is identical to the nominative.

Can the word order change? For example, Я перед уходом закрываю окно or Я закрываю окно перед уходом?

Yes. Russian word order is flexible and shifts focus:

Перед уходом я закрываю окно (emphasizes the time)
Я перед уходом закрываю окно (neutral)
Я закрываю окно перед уходом (emphasizes the action)

Are there other ways to say “before leaving” besides перед уходом?

Yes, you can use subordinate clauses with the infinitive:

Прежде чем уйти, я закрываю окно. (formal)
Перед тем как уйти, я закрываю окно. (common)

What’s the difference between перед уходом and the gerund уходя (as in Уходя, я закрываю окно)?

Перед уходом is a noun phrase + preposition, stating time explicitly (“before departure”).
Уходя is a gerund (деепричастие) meaning “while leaving,” implying two simultaneous or sequential actions by the same subject. The gerund focuses on the manner/timing, not routine.