The generation gap is difficult for both the younger and the older generations.代沟使青老两代人都感到别扭。The book graphs and annotates the hostility between generations.本书描绘并诠释了两代人之间的敌意。A credibility gap is almost inescapable between the generations.两代人之间的互不信任几乎是不可避免的。The disease gradually died out over the last two generations.这种疾病在上两代人那里逐渐消失了。