It has been necessary to refer repeatedly to the effects of the two world wars in promoting all kinds of innovation. It should be (62) also that technological innovations have (63) the character of war itself by the () of new mechanical and chemical devices. One weapon developed (65) World War II deserves a special mention. The (66) of rocket propulsion (推进力) was wellknown earlier, and its possibilities as a (67) of achieving speeds sufficient to escape from the Earth’s gravitational (引力的) pull had been (68) out by the Russian and the American scientists. The (69) built an experimental liquid-fuelled rocket in 1926. (70) , 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 (71) of delivering a warhead hundreds of miles away. Reaching a height of over 100 miles, the V-2 rocket (72) the beginning of the Space Age, and members of its design team were (73) in both the Soviet and United States space programs after the war. Technology had a tremendous social (74) 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, (75) a process of rapid ization and a virtual revolution (76) living through mass production of household goods and (77) . The rapid development of the airplane, the cinema, (78) radio made the world seem suddenly smaller and more (79) . The development of many products of the chemical industry further transformed the life of (80) people. In the years following 1945 the constructive and creative opportunities of modern technology could be exploited, (81) the process has not been without its problems.