上古汉语的“主+之+谓(+也)”结构经常充当后面主句的时间从句。结构助词“之”和语气助词“也”是使普通的“主+谓”结构降级为从句的重要语法手段,它们在上古汉语的复合句结构中起到了显示主句和从句之间关系的作用,因此可以把它们看作从句关系标记。 The “+ + +” (+) “structure of ancient Chinese often acts as a time clause of the main clause behind. The structural auxiliary word ”“ and the modal particle ”also “ are the important grammatical means to downgrade the ordinary ”main + predicate " structure to the clause. They play the role of displaying the main clause in the compound sentence structure of the ancient Chinese The role of the relationship between the clauses, so they can be regarded as clauses markings.