Dawn on : [for a fact] to become apparent to someone; [for something] to be suddenly realized by someone. (Upon is formal and less commonly used than on.) This expression transfers the beginning of daylight to the beginning of a thought process. Harriet Beecher Stowe had it in Uncle Tom’s Cabin (1852): “The idea that they had either feelings or rights had never dawned upon her.” [Mid-1800s].
中文释义：说到dawn这个单词，很多人会想到黎明、拂晓、破晓，是一个名词。dawn除了做名词，还可以做动词：dawn on someone 或者dawn upon someone ,（upon适用于更正式的场合，使用频率较低），均表示某人突然明白了（意识到）某事，某事被某人看清了。例句：Suddenly it dawned on me that they couldn’t possibly have met before.（我突然明白他们以前不可能见过面）。另外引申几个与dawn相关的习语和短语：break of dawn（破晓、黎明）；at the crack of dawn（ 黎明、破晓、清晨 ）。