The complex sentence is a sentence that consists of an independent clause and one or more dependent clauses, introduced, and joined with the linking word, called subordinating conjunctions. There are a lot of subordinate conjunctions in English language. Some of the commonly used subordinate conjunctions are: as, as if, before, after, because, though, even though, while, when, whenever, if, during, as soon as, as long as, since, until, unless, where, and wherever. For ex, As the bridge wasn’t properly maintained by the government, it fell down.