Prodigious efforts主语
accelerated during two world wars定语
were required 系表(谓语)
before the technology of primitive rocketry could be translated into the reality of sophisticated astronauts时间状语
Prodigious efforts主语
accelerated during two world wars定语
were required 系表(谓语)
before the technology of primitive rocketry could be translated into the reality of sophisticated astronauts时间状语