1.Not until dark did the boys realize it was too late to return.2.No sooner had I closed my eyes than the phone rang.3.Only when that class was over was he able to play football with his friends.4.So fast does light travel that it is difficult for us to imagine its speed5.Never shall I forget the day when I joined the League.6.Had there been no computers,there would have been no man-made satellites or rockets. 1.Not until dark did the boys realize it was too late to return.2.No sooner had I closed my eyes than the phone rang.3.Only when that class was over was he able to play football with his friends.4.So fast does light travel that it is difficult for us to imagine its speed5.Never shall I forget the day when I joined the League.6.Had there been no computers,there would have been no man-made satellites or rockets.