he was beginning to cross the road as a car knocked the boy over.
问题描述：
he was beginning to cross the road as a car knocked the boy over.
答
那个男孩正准备过马路的时候,这时一个汽车把他撞倒了.把as 放到前面有没有影响？as a car knocked the boy over，he was begnning to cross the road.这样子呢可以的，没有什么影响。