1.high 在这个短语中是个形容词,修饰后面的名词praise2.high 和highly 做副词时是有区别的,high指有具体的高度,而highly 往往具有抽象的意义The plane fly high in the sky. speak highly of sb.类似的区别还有deep, deeply \ wide, widely
the most important matter of a person is his/her lofty character rather than his/her class origin. 或者:what matters to a person is his/her lofty character rather than his/her class origin.