When reading ancient poems, what kind of complex emotions did Du Fu's poems express?

① Sorrow in travel: escaping from war all the year round, wandering in remote places, drag out an ignoble existence and crying;

(2) Sigh of old age and illness: The author is dying, sick, lonely and full of lament;

3 Heart is the imperial court: don't forget your kindness in your heart, and always look north at Chang 'an;

4 suffering from no bosom friend: sighing for many years, no bosom friend listening and understanding.