The art of pleasing is a very necessary one to possess, but a very difficult one to acquire, for it can hardly be ______ to rules.
 
【正确答案】 C
【答案解析】reduce to sth将某事物概括为或简化为某种形式。deduce演绎,推断。conduce to有助于,有益于。induce劝诱,促使。