Questions & Answers about Летом я плаваю в реке.
What is Летом? Why is there no preposition, and why does it end in -ом?
Летом is the instrumental-case form of лето used adverbially to express “when.” In Russian, seasons (and some times of day) often take the instrumental suffix and drop any preposition to mean “in/during [that season].” Compare: утром (“in the morning”), ночью (“at night”).
Why is the verb плаваю used instead of плыву?
Russian has two imperfective verbs for “to swim”:
- плыть (unidirectional) describes a single, continuous movement in one direction.
- плавать (multidirectional) describes habitual, repeated, or general swimming ability.
Here плаваю (1 sg. present of плавать) tells us “I habitually swim” or “I can swim,” fitting the meaning “I swim regularly in the river during summer.”
Why is в реке in the prepositional case rather than accusative?
With the preposition в, you choose accusative for motion into something, but prepositional for location in something.
- в реку (acc.) = “into the river” (movement).
- в реке (prep.) = “in the river” (where the swimming happens).
Since you’re describing where you swim, you use the prepositional: в реке.