Breakdown of Зимой там нельзя купаться.
там
there
зимой
in winter
нельзя
one must not
купаться
to swim (bathe, recreationally)
Questions & Answers about Зимой там нельзя купаться.
How does нельзя work in this sentence, and where is the subject?
нельзя is an impersonal word meaning "it is not allowed" or "one must not." Because it is impersonal, the sentence doesn't have a grammatical subject like "I" or "they"—it just states a general rule.
Why is купаться in the imperfective aspect here?
When нельзя is used to mean "forbidden" or "not allowed," it is always followed by an imperfective verb like купаться. If you were to use a perfective verb instead, нельзя would change meaning to indicate that an action is physically impossible, rather than just against the rules.
Why does the sentence use зимой instead of the dictionary form зима?
зимой is the instrumental case form of зима (winter). Russian uses the instrumental case for seasons and parts of the day to express "in the" or "during the". So, зима is the noun "winter," while зимой means "in winter."
I've also learned the verb плавать for "to swim." Why use купаться here?
плавать refers to the physical action or sport of swimming, like swimming laps in a pool. купаться is closer to "bathing" or splashing in the water for fun, which is exactly what people usually mean when they go swimming at a beach or a lake.