The main difference between the terrorism in 1970' s, 1980' s and 1990' s is______.

A．A ) cyberspace will become a new medium for terrorism
B．terrorism will become the outcome of competition between terrorists and countries
C．C ) terrorists find it hard to control their actions because of informational technology
D．terrorists will take the advantage of technology to attack any country in the world.

A．the future war will be non-military war or net-war
B．the future war will be waged between groups and nations
C．the future war is most likely to depend more on high technology
D．economy will become the focus of war in the future