Final answer:
A simple sentence consists of a single independent clause that contains a subject and a predicate, forming a complete thought on its own.
Step-by-step explanation:
A simple sentence consists of a single independent clause. An independent clause contains a subject and a predicate and can stand alone as a sentence. For example, the sentence "The coronavirus spread around in the world in 2020." is a simple sentence because it expresses a complete thought and does not depend on any additional clauses. It is important to understand that a simple sentence is not necessarily short; it can be lengthy as long as it contains only one independent clause and expresses a single idea.