单选题 .  A schoolboy's life is in preparation for the real battle of life. It is also     21    of differences and interests. One of the     22    important parts of a schoolboy's life is to get     23    knowledge and good mind-training as he can. His     24    business in school is to learn. He     25    to read the book he is     26    in the classes. He has to do the homework set to him.     27    part that     28    a schoolboy's life is discipline. At school there are     29    rules     30    . This strict discipline is very     31    for him when he     32    society to     33    a living. It teaches him some very necessary virtues on the road to a     34    life.
    School is a place for a schoolboy to learn what the social life is     35    .     36    in the classroom and the playground, he has to catch up with his fellows and not members of his family.
    He can not behave     37    he does in his home. He is no longer a spoiled child, and his school fellows will not give     38    to his wishes. He soon gets his corners robbed of and learns the lesson of give-and-take, good manners, and thought for     39    .
    This is     40    the way when he has to carry himself in society.21.