Specifically:
1. "Hot years" means that young time is like a burning flame, full of vitality and passion.
2. "Full of blood" means that the heart is full of blood and shows strong desire and determination.
3. "No regrets youth" emphasizes cherishing youth, and no matter what difficulties or setbacks you encounter, you will never regret or feel sorry.
4. "Reflecting the sun and the moon" means that youth illuminates the day and night and makes life more brilliant.
This poem expresses the poet's love and pursuit of young time, as well as his yearning for a full and meaningful youth life. It emphasizes the preciousness of youth, encourages people to actively and enthusiastically pursue their dreams and goals, and is not afraid of setbacks and does not regret everything they have experienced.