There are many features that 【B1】 a movie as American, but perhaps the most 【B2】 is the theme of the loner-hero (孤胆英雄). In the western movie, which comes out of many 【B3】 of the American West, a typical figure is the lonesome cowboy. He wanders into a town and 【B4】 out its troubles. Then the strong and independent hero rides off into the sunset 【B5】 . Americans like this 【B6】 in their films because they are 【B7】 independent, and individualism 【B8】 a great deal with them. An individual, who is able to 【B9】 the evils of the world, or of a small town, is someone to admire. Even the gangster movie, a very popular 【B10】 of the typical American film, usually has a hero. 【B11】 he is a lawman out to catch the criminals or a gangster who suddenly sees the light and tries to go 【B12】 . During the violence-ridden period of Prohibition in the 1920s, the gangster movie 【B13】 in popularity. These films kept the same 【B14】 as the western — the bad cannot triumph. One good person can save the innocent. Recent science fiction films deal 【B15】 the same theme. Against the forces of the alien powers, people will fight to protect their ideals. Here, too, the action 【B16】 around a single individual, 【B17】 now he or she must save the world. The hero battles the unknown, trusting in inner capabilities and in the power of good 【B18】 evil. Fearless, the hero of a typical American movie does not 【B19】 to jump into the action. This dominant theme of the American movie is familiar 【B20】 people around the world.

A．essential
B．important
C．significant
D．necessary