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。