The entities of an event participate in the event in different ways, for instance: in the sentence 刚才张三在烛火上烧了那封信。‘Gāngcái Zhāng Sān zài zhúhuǒ shàng shāo le nà fēngxìn’ (Just now Zhang San burned the letter in the candle’s fire), the subject NP 张三‘Zhāng Sān’ in the active event of ‘burning the letter’ plays the role of the agentive participant, because he performs the action intentionally and responsibly, the object NP 那封信‘nà fēngxìn’ (that letter) is acted on by Zhang San’s action and it is affected in such a way that it comes out changed, so the object argument plays the role of Patient or an affected participant. In the event the nonparticipants, the adverbial elements of time and place also play semantic roles; they denote the circumstances of the event: the time (刚才‘gāngcái’ (just now)) and location (在烛火上‘zài zhúhuǒ shàng’ (on the candle flame)) of the happening of the event, it can also be analyzed as the Instrument with which to conduct the event of burning the letter as well.
[1] Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.