Not until he crossed the line and felt the tape snap against his chest did Johnson know he had won the race.（loose sentence）
Johnson did not know that he had won the race until he crossed the line and felt the tape snap against his chest.
Not until he crossed the line and felt the tape snap against his chest did Johnson know he had won the race.（loose sentence）
Johnson did not know that he had won the race until he crossed the line and felt the tape snap against his chest.
