Subordinating conjunctions join a subordinate clause and a main clause. There are several types of subordinating conjunctions including those indicating time (e.g. before, after), those indicating purpose (e.g. that, in order that), those indicating cause or reason (e.g. because, since), those indicating result (e.g. so...that), those indicating condition (e.g. if, unless), those indicating contrast (e.g. though, although), and those indicating comparison (e.g. than).