What makes a sentence complex?

A complex sentence is defined by the presence of an independent clause combined with at least one dependent clause. The independent clause can stand alone as a complete thought, while the dependent clause adds additional information but cannot function independently as a complete sentence. This combination allows for greater depth and complexity in writing, as it can convey more nuanced ideas and relationships between those ideas.

For example, in the sentence "Although it was raining, we decided to go for a walk," "Although it was raining" is a dependent clause that cannot stand alone, while "we decided to go for a walk" is an independent clause that does convey a complete thought. Together, they form a complex sentence that enriches the meaning.

The other options describe different types of sentence structures: multiple independent clauses indicate a compound sentence, a series of short fragments typically results in incomplete thoughts, and sentences comprised solely of dependent clauses are not complete and cannot express a full idea independently. Thus, the defining characteristic of a complex sentence is the combination of an independent clause with at least one dependent clause.