问答题 1.  The world has changed. The fall of the Berlin Wall in 1989 and the dissolution of the Soviet Union in 1991 marked the end of Cold War confrontation between the two major power blocs, which is undoubtedly the most important political transformation of the last few years. What has this meant for world peace? The geopolitical interpretation, perhaps the commonest, maintains that bipolarity based on the existence of two nuclear powers of equal strength was the guarantee of peace over the last forty years. Now that this balance of terror has disappeared, all kinds of wars are once again possible.