It has been necessary to refer repeatedly to the effects of the two world wars in promotin

It has been necessary to refer repeatedly to the effects of the two world wars in promoting all kinds of innovation. It should be【C1】______ also that technological innovations have【C2】______ the character of war itself by the【C3】______ of new mechanical and chemical devices. One weapon developed【C4】______ World War II deserves a special mention. The【C5】______ of rocket propulsion (推进力) was wellknown earlier, and its possibilities as a 【C6】______ of achieving speeds sufficient to escape from the Earth"s gravitational (引力的) pull had been【C7】______ out by the Russian and the American scientists. The【C8】______ built an experimental liquid-fuelled rocket in 1926.【C9】______ , a group of German and Romanian pioneers was working across the same lines, and in the 1930s, it was this team that developed a rocket【C10】______ of delivering a warhead hundreds of miles away. Reaching a height of over 100 miles, the V-2 rocket【C11】______ the beginning of the Space Age, and members of its design team were【C12】______ in both the Soviet and United States space programs after the war. Technology had a tremendous social【C13】______ in the period 1900—1945. The automobile and electric power, on the other hand, radically changed both the scale and the quality of 20th-century life,【C14】______ a process of rapid urbanization and a virtual revolution【C15】______ living through mass production of household goods and【C16】______ . The rapid development of the airplane, the cinema,【C17】______ radio made the world seem suddenly smaller and more【C18】______ . The development of many products of the chemical industry further transformed the life of【C19】______ people. In the years following 1945 the constructive and creative opportunities of modern technology could be exploited,【C20】______ the process has not been without its problems.

【C1】

A．observed

B．notified

C．commented

D．detected