would take ...before.有什么语法知识吗?

it would take another war before the federal government would act on a national highway system.
为什么翻译书是翻译成,在另一场战争发生之后,联邦政府才着手建立一个全国性的公路系统?
我自己翻译是：联邦政府建立一个全国性的公路系统后,将会导致另一场战争的发生.
答：正确,合理的翻译离不开上下文及对句子的正确理解.
上文是：Early in the 20th century,most of the streets and roads in the U.S.were made of dirt,brick,and cedar wood blocks.Built for horse,carriage,and foot traffic,they were usually poorly cared for and too narrow to accommodate(容纳)automobiles.
With the increase in auto production,private turnpike(收费公路)companies under local authorities began to spring up,and by 1921 there were 387,000 miles of paved roads.Many were built using specifications of 19th century Scottish engineers Thomas Telford and John Mac Adam(for whom the macadam surface is named),whose specifications stressed the importance of adequate drainage.Beyond that,there were no national standards for size,weight restrictions,or commercial signs.During World War I,roads throughout the country were nearly destroyed by the weight of trucks.When General Eisenhower returned from Germany in 1919,after serving in the U.S.Army’s first transcontinental motor convoy(车队),he noted:“The old convoy had started me thinking about good,two-lane highways,but Germany’s Autobahn or motorway had made me see the wisdom of broader ribbons across the land.”
本句结构是：It would take sth.before sb.would do sth.
注意这个时间状语从句中的情态动词would!这里表示愿意!这里讲的是过去将来的事,如果是将来的事,一般说：it will take some time/ sth.before sth.happens 在某事发生之前,将需要多少时间（/将需要什么东西）（或译：需要多久之后,才会发生某事）.时间状语从句中是不用will表示将来的,而用一般现在时.如果用了will,那不是表将来,而是表意愿.
所以作者说：在联邦政府愿意建立一个全国性的公路系统之前,还需要另一场战争.
或译：要再发生一场战争之后,联邦政府才会去建立一个全国性的公路系统.
请看下文：
It would take another war before the federal government would act on a national highway system.During World War II,a tremendous increase in trucks and new roads were required.The war demonstrate how critical highways were to the defense effort.Thirteen per cent of defense plants received all their supplies by truck,and almost all other plants shipped more than half of their products by vehicle.The war also revealed that local control of highways had led to a confusing variety of design standards.Even federal and state highways did not follow basic standards.Some states allowed trucks up to 36,000 pounds,while others restricted anything over 7,000 pounds.A government study recommended a national highway system of 33,920 miles,and Congress soon passed the Federal-Aid Highway Act of 1944,which called for strict,centrally controlled design criteria.