dawn在这个意思和用法里是不用于被动语态的。其实，这是个固定搭配的句型 It suddenly dawned on sb. that… ，不必纠结。请看
【短语动词】dawn on sb (also 'dawn upon sb more formal)
【解释词义】[no passive ] if an idea, the truth or a fact dawns on you, you realize it for the first time
【汉语意思】使开始明白；使渐渐领悟；使开始理解:
【简单例句】It suddenly dawned on us that we were lost.我们突然意识到我们迷路了。
The answer finally dawned on me.我最终找到了答案。
【新概念英语第三册 37课 】 It suddenly dawned on me that this express was not roaring down the line at ninety miles an hour, but barely chugging along at thirty.我突然感到这趟快车并没以时速90英里的速度呼啸前进，而是卟哧卟哧地向前爬行，时速仅30英里。
