In the text, Fanka wrote a letter to his grandfather. What was the tone of the letter?

In the text "Fanka", Fanka wrote a letter to his grandfather with a bitter tone. He described the poverty and predicament of his life and expressed his dissatisfaction and resistance to poverty and injustice. In the letter, Fanka also expressed his gratitude and longing for his grandfather, but his living conditions and state of mind were still inseparable from poverty and suffering. Therefore, Fanka's tone in writing to his grandfather was bitter.