咬文嚼字。解释加线的字的意思，再说说句意。
(1)人之初 性本善 性相近 习相远
__________________________________________________________
(2)苟不教 性乃迁 教之道 贵以专
__________________________________________________________
(3)玉不琢 不成器 人不学 不知义
__________________________________________________________