Ever since he was hit by a car, he has walked with a limp.

請問老師前面是Ever since 引導的時間狀語從句嗎？

是的。又如：

I have known him ever since I was a child.我自孩提年代起就已經認識他了。
Ever since he lost his job, he has been looking rather down at the heels.從他失業以來, 他的樣子一直那樣邋遢。