ВとНАの使い分け

"The New Penguin Russian Course"の50ページより抜粋：

"In" is В, "on" is НА, "at" will be В with enclosed spaces or buildings (at school / в школе) and НА with open spaces and activities/events (at work / на работе; at concert / на концерте). Note that English "in" sometimes corresponds to Russian НА when the place (e.g. a street) is an open space or was originally an open space (e.g. вокзал / "Station")

　簡単に言うと、閉鎖された空間や建物と一緒に使われる "at" の時は "В" を使い、開かれた空間やイベントなどと一緒に使われる "at" の時は "НА" を使う、ということらしい。使い分けのために覚えておこう。