A. It marks the arrival of the hottest period of the year, reminding people to take precautions against heatstroke

B. It signifies the complete ripening of summer grains and is a festival for celebrating the harvest

C. It describes the stage where summer crops have begun to plump up in the ear but are not yet fully mature, embodying the philosophical idea that "fullness invites loss, humility receives benefit."

D. It indicates that rainfall has peaked across the country, requiring focused efforts on flood prevention