Compound Sentence
Find the clause boundaries first. If both sides contain an independent clause, coordination can create a compound sentence; if one clause depends on the other, the result is complex instead. Punctuation depends on how the independent clauses are joined.
A compound sentence contains at least two independent clauses joined by coordination or by punctuation that can link independent clauses. Each main clause could stand as a sentence on its own; merely containing “and” does not make a sentence compound.
Key details
Further guidance
Clause Test
Test each major part independently. In “Mina drafted the report, and Leo checked the figures,” both “Mina drafted the report” and “Leo checked the figures” can stand alone.
Not Every And
“Mina drafted and revised the report” is one independent clause with a compound predicate, not a compound sentence.
Punctuation
When a coordinating conjunction joins two independent clauses, a comma normally marks the clause boundary. A semicolon can join closely related independent clauses without a coordinator.
Worked Example
“The data were incomplete, so we repeated the test” is compound because both clauses are independent. “We repeated the test because the data were incomplete” is complex because the because-clause is dependent.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Sentences (opens in a new tab)Cambridge University Press · Cambridge defines a simple sentence structurally as a sentence with only one main clause, contrasting it with compound and complex sentence structures.
- Sentence Variety (opens in a new tab)Purdue Online Writing Lab · Supports the bounded task of identifying and constructing coordinated independent clauses while distinguishing complex structures.