(2) Change: from peaceful improvement to violent revolution. Reasons: the bourgeois reform movement failed, and the road of peaceful improvement did not work;
At the beginning of the 20th century, the Qing government was completely reduced to a tool for imperialism to rule China. Results: The rule of the Qing Dynasty was overthrown and the feudal autocratic monarchy system of more than two thousand years was ended.
(3) mainstream public opinion: the national revolution is the most important plan to save the country; The positive influence of the Soviet Union on China has surpassed that of the United States; Lenin and Sun Yat-sen occupy an important position in people's minds. Reasons: the influence of the southern revolution; The spread of Russian October Revolution in China: the New Culture Movement and the May 4th Movement promoted people's ideological emancipation; The reactionary rule of warlords. Influence: The first cooperation between the two parties set off a vigorous national revolution.
(4) Take national development as its own responsibility; The revolutionary spirit of keeping pace with the times. (Answer only one of them)