确定有主句的子系统可以从两个角度入手，一是主语角度，一是谓语角度。从主语角度看，能作主语的语法单位有代词、名词、数词、动词、形容词、名词和名词构成的联合词组、同位词组、“的”字词组、数量词组、主谓词组、动宾词组、偏正词组等等，因为主语一般是传达旧信息的，? Determine the main clause of the subsystem can start from two perspectives, one subject angle, one predicate perspective. From the perspective of the subject, the grammatical units that can serve as the subject are the pronoun, the noun, the numeral, the verb, the adjective, the noun phrase and the noun combination phrase, the collocation phrase, the word phrase, the quantifier phrase, the verb phrase, Phrase, partial orthonormal phrase, etc., because the subject is generally to convey the old information?