Lesson 4: Sentence Structure: Simple and Compound Sentences

Definition

A simple sentence has one and only one independent clause. It has no subordinate clauses.

A compound sentence has two or more independent clauses. It has no subordinate clauses.

Explanation

Think of a simple sentence as a complete thought standing on its own, like a solo singer. Even if it has a compound subject or verb (like 'Mom and Dad' or 'ran and jumped'), it's still just one independent clause. A compound sentence links two or more of these complete thoughts together, like a duet or a group performance. Each part could be its own sentence, but they are joined to show a close relationship.

Examples

Simple Sentence

• The birds sang sweetly from the tall oak tree. [This sentence has one independent clause with prepositional phrases.]
• My dog barks and wags his tail. [This sentence has one independent clause with a compound verb.]
• The sun and the moon light up the sky. [This sentence has one independent clause with a compound subject.]

Compound Sentence

• The thunder roared, and the rain began to fall. [This sentence contains two independent clauses joined by a comma and a conjunction.]
• We packed our bags, we drove to the airport, and then we boarded the plane. [This sentence contains three independent clauses.]

Definition

Simple sentences can be joined to form compound sentences in one of three ways: with a comma and a coordinating conjunction, with a semicolon, or with a semicolon, a conjunctive adverb, and a comma.

Explanation

Joining two complete thoughts requires the right punctuation. Using a comma and a coordinating conjunction (like and, but, or) is the most common way to link ideas. A semicolon creates a stronger, more direct link between two closely related independent clauses. For an even more specific connection, use a semicolon with a conjunctive adverb (like however, therefore) to show contrast or cause and effect.

Examples

• The concert was loud, so we moved to the back. [A comma and a coordinating conjunction join the clauses.]
• Maria excels at math; her sister prefers history. [A semicolon joins two closely related independent clauses.]
• Our team practiced every day; therefore, we were confident we would win. [A semicolon, a conjunctive adverb, and a comma are used to link the clauses.]