That system, __, is displacing a national system of communications which __ at the end of the 19th century __ the railroad and telegraph, and was ‘perfected’ in subsequent innovations through television in the network era.”（ ） A.came into existence B.as a result of C.access to D.in turn

That system, __, is displacing a national system of communications which __ at the end of the 19th century __ the railroad and telegraph, and was ‘perfected’ in subsequent innovations through television in the network era.”（ ） A.came into existence B.as a result of C.access to D.in turn

正确答案：ABD