单选题 .  Culture is activity of thought, and receptiveness to beauty and humane feeling.     1    of information have nothing to do with it. A merely well-informed man is the most useless     2    on God's earth. What we should     3    at producing is men who     4    both culture and expert knowledge in some special direction. Their expert knowledge will give them the ground to start     5    , and their culture will lead them as     6    as philosophy and as high as     7    . We have to remember that the valuable     8    development is self-development, and that it     9    takes place between the ages of sixteen and thirty. As to training, the most important part is given by mothers before the age of twelve.
    In training a child to activity of thought, above all things we must     10    of what I will call "inert ideas"—that is to say, ideas that are merely     11    into the mind without being     12    , or tested, or thrown into fresh combinations. In the history of education, the most     13    phenomenon is that schools of learning, which at one epoch are alive with a craze for genius, in a     14    generation exhibit merely pedantry and routine. The reason is that they are overladen with inert ideas. Except at     15    intervals of intellectual motivation, education in the past has been radically     16    with inert ideas. That is the reason why     17    clever women, who have seen much of the world, are in middle life so much the most cultured part of the community. They have been saved from this horrible     18    of inert ideas. Every intellectual revolution which has ever stirred humanity     19    greatness has been a     20    protest against inert ideas.1.