What characterizes a complex sentence?

A complex sentence is distinguished by its structure, which includes one independent clause and at least one dependent clause. The independent clause expresses a complete thought and can stand alone as a sentence, while the dependent clause does not convey a complete thought and relies on the independent clause to provide context.

For example, in the sentence "Although it was raining, we went for a walk," "we went for a walk" is the independent clause, and "Although it was raining" is the dependent clause. This combination creates a nuanced thought, allowing for a more sophisticated expression of ideas.

The other options do not appropriately define a complex sentence. A sentence with only one independent clause characterizes a simple sentence, whereas multiple independent clauses would suggest a compound sentence. A single phrase without a subject is not considered a sentence at all. Thus, the presence of both an independent clause and a dependent clause is what distinctly identifies a complex sentence.