1、The clouds which filled the sky at break of day have disappeared.
破曉時滿天的云已經消失了。

2、At break of day the hikers were already on the trail
黎明時分，那些徒步旅行者已經上路。

3、They walked the whole night long, and by break of day came once more to their father's house.
他們走了整整一夜，天剛亮時又回到了父親的家。