Mathesius named the starting component as theme,and named the other components as rheme,at the same time,the theme showed known information,the rheme showed new information.他把这类起点成分称为主位，把其他部分称为述位，并指出，主位一般表示已知信息，述位一般表示新信息。
Rheme, on the other hand, is the part of a sentence which adds most to advancing the process of communication and has the highest degree of communicative dynamism.述位，另一方面，是一个组成部分，一句是增加最与时俱进的过程中的沟通和具有最高程度的交际动力。
