In a sentence that has a direct object, the typical semantic role of the subject is that of the agentive participant—normally a human who volitionally or intentionally conducts the action denoted by the verb:
Xuésheng men zài dǎsǎo jiàoshì.
(The students are cleaning the classroom.)
In sentence (1), the subject 学生们‘xuésheng men’ (students) has the semantic role of Agent.
 Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.