误At the dawn the guests departed.
正At dawn the guests departed.
一大早,他们便起床出发了。误At early dawn, they got up and set off.
正At the early dawn, they got up and set off.
析at dawn〔before dawn, from dawn〕 till dark等短语中不可加the,但在at the early dawn, with the dawn等短语中一定要加the。