если бы джон не прикрепил значок на

если бы джон не прикрепил значок на рубашку, я бы не узнал что он участник конференции

Результаты (английский) 1:

If John does not tacked icon on the shirt, I would not have learned that he was a participant of the Conference

Результаты (английский) 2:

If John had not attached the badge on his shirt, I would not have known that he was a participant of the conference

Результаты (английский) 3:

if john doesn't put a badge on his shirt, i don't know he's a member of the conference