xpansion.These phenomenons give American plex new meaning.Рthe civil warРwestward movementРCrisis consciousnessРAmericans have long crisis consciousness . American has gradually e the most powerful country in the world after two world wars,the Cold war and the 9/11. There are many crises in American society beneath the strong surface. There is a sense of insecurity in subconscious from hostile countries, (敌对国家)natural disasters, etc.So, personal heroism meets the needs of American society and the lack of security.РThe development of film technologyРWith the development of film technology,the effects of high-end (高端)technology have been wildly used in the film,making these heroic roles be equal to anything(无所不能).These heroic films make the American plex spread and develop all over the wold.