This question examines the role of science and technology. Advanced production tools are the materialization of people's advanced science and technology, and their application in the production process will accelerate the development of production and improve the efficiency of production. The scientific and technological revolution promotes the change of production mode, and then promotes the change of social system. In this subject, hand mill and steam mill are advanced production tools and the materialization of science and technology. Because of their wide application, they promoted the transformation of production mode and produced feudal society and industrial capitalist society respectively. Therefore, AC is correct and option B is obviously wrong. Science and technology are not the only decisive force for historical change. Science and technology are indirect productive forces, not independent forces. Independent power can only be workers who use science and technology. Option d is wrong. Therefore, the correct answer to this question is AC option.