Question

they_chess for three hours__ Tom entered the room.
A) were playing, till
B) Are playing, if
C) had been playing, when
D)played,since
E) were playing, as soon as​

Answer 1

Ответ:

they had been playing chess for three hours when Tom entered the room

Объяснение:

хз А и Д по смыслу больше подходит но С звучит будто оно там так и должно быть, обычно уточняют время когда пишется have/had been