Sentences are built from clauses (Independent and Dependent Clauses). Counting them tells you a sentence’s structure. The first two structures use only independent clauses.
- A simple sentence has one independent clause. It can still be long, with phrases and compound parts: “Ana and her brother washed and dried the dishes after dinner.”
- A compound sentence has two or more independent clauses, joined by a comma and a coordinating conjunction (for, and, nor, but, or, yet, so) or by a semicolon: “The rain stopped, and the sun came out.” “The bell rang; class was over.”
Key idea
Count subject–verb pairs that could each stand alone. One: simple. Two or more, joined: compound.
Why it works
A compound sentence shows that two ideas are equal partners, and the conjunction says how they relate (and adds, but contrasts, so gives a result). The comma before the conjunction tells the reader a new clause is starting.
Worked example: A compound verb is not a compound sentence
Is “Leo sang and danced at the party” simple or compound?
- Subject: Leo. Verbs: sang and danced.
- After and there is no new subject, so there is only one clause.
Answer: simple (with a compound verb)
Worked example: Two clauses
Is “Leo sang, and Mia danced” simple or compound?
- First clause: Leo sang. Second clause: Mia danced.
- Each could stand alone, and they are joined by a comma and and.
Answer: compound
Common mistake
Calling a sentence with a compound verb a compound sentence. “Leo sang and danced” is simple: one subject, one clause. Check whether the words after the conjunction have their own subject.