Illustrate the change of Li Bai's poetic style with examples.

(1) Unfortunate talents and untimely birth are the common tone of Li Bai's poems, accompanied by a sense of political abandonment and no place to return. When Li Bai was young, he had a strong desire for fame and fortune, and he was "conceited for worldly affairs." This strong concept of charity obviously comes from the Confucian idea of governing the country and calming the world. However, Li Bai is not an ordinary scholar. As a romantic poet, his chivalrous character and unique temperament, that is, his rich imagination and whimsy divorced from reality, came from the Confucian thought of helping others, and melted into the catalyst of the poet's own subjective spirit, which naturally expanded into arrogance, conceit and fame and fortune. However, Li Bai's arrogance and conceit are often inconsistent with reality, which makes the poet feel helpless about his political future.

(2) If the sense of political abandonment and loneliness without a sense of refuge are caused by the conflict between the poet's ideal, the poet's personality and the environment. Then, Li Bai's loneliness can only be said to come from the poet's subject and personality itself. This is the loneliness that the poet is aloof, arrogant and unwilling to walk with the world. Let's call it loneliness of self-exile. The loneliness of self-exile can especially show the strength and brilliance of the poet's character. Li Bai has a very strong sense of self. His chivalrous and romantic character, coupled with his natural talent and good education, often makes him feel pretentious and superior. Searching for a bosom friend embodies Li Bai's strong desire for the world. The sigh of bosom friend's peace of mind also reflects the unique loneliness in this world, and of course reveals the pride of Chun Xue.

(3) In some of Li Bai's poems, there is also a sadness of crossing the world. "The living are passers-by, and the dead are returnees. Heaven and earth go against each other, sharing the same sorrow and dust. " It is precisely because the poet is aware of the irreversible natural laws of life and the universe that he can realize this desolate loneliness consciousness in this strong contrast between finite and infinite, death and eternity.