not until 구문

[경 꿈 사]

* I didn't fall asleep until the dawn began to appear. a)
= Not until the dawn began to appear did I fall asleep. b)
= It was not until the dawn began to appear that I fell asleep. c)
not until구문인데요..
a)문장에서 c)문장으로 어떻게 변화게 되었는지 아시는 분 계세요?

[내년인가?]

it was~that~ 강조 구문이네요.

[잉어빵]

a--->b(부정어가 앞으로 나가고 도치구문)---->c(it~that강조구문, it과 that사이에 강조할 부분을 넣음)