Conjunctive particles of Japanese to and -tara have a common use for connecting two events. The purpose of this paper is to distinguish the usages of to and -tara in detail. The original use of to represents two events with the same subject, which occur volitionally and successively. The -tara, however, has no such usage. It connects two events with causation or explanation relation. In this case, it cannot be replaced by to.
1. 들어가는 말
3.「 －たら」의 접속의 성격