Different from an independent clause, a dependent clause does not express as complete though or does not contain both a subject and verb, due to this, dependent clauses cannot stand by themselves and need other sentences to be complete. The clause "if the singer doesn’t show up" is a dependent clause because this does not express a complete idea as the word "if" suggests a condition or consequence that has not been included, for example, "if the singer doesn't show up we will leave", this means the clause is not complete, cannot stand alone and thus, is dependent.
