Quote Originally Posted by Antonio1986 View Post
Pochemu net edinstvennoe chislo? Vo vremya probezhki ...
Good question! Во время + singular references to a single act of something, and во время + plural references to a sequence of repetitive actions as a whole. Not sure what exactly verbal nouns are covered with this rule. At least, it seems many verbal nouns ending with -ка fit into the pattern:
во время пробежки/пробежек
во время прогулки/прогулок
во время разведки/разведок
во время атаки/атак
But not all of them: во время рыбалок sounds unusual.