In the long history of the world, only a few generations have been granted the role of defending freedom in its hour of maximum danger. 在世界的悠久历史中，只有很少几个世代的人赋有这种在自由遭遇最大危机时保卫自由的任务。 I do not shrink from
So, a problem in explaining how children learn language, 所以在解释孩子们如何学习语言时候，有一个问题 a problem in teaching language to adults so that they don't make grammatical errors, 同样也是教成人学外语语法时的一个问题 and a problem in
