In order to reduce the unnecessary waste of limit network resources such as network bandwidth,communication cost,and agents' energy,the investigation of event-triggered schemes has become a hot research topic and attracted numerous scholars' attention.This paper mainly discusses several classical event-triggered schemes,i.e.centralized,clustered and distributed event-triggered schemes,self-triggered schemes and edge event-triggered schemes.The research background and the recent results about the above schemes are specifically introduced.Note that the exclusion of Zeno behavior is a key problem of analyzing the effectiveness of event-triggered schemes.This paper points out a flaw of excluding Zeno behavior in the early related research,and then summarizes two basic methods to avoid this behavior.Finally,this paper provides some future research works of event-triggered schemes,and their theoretical or application research.