Complete sentences and boundaries
Recognise independent clauses and avoid joining them with only a comma.
Before you begin
- Subjects and verbs
- Basic punctuation
Identify a complete clause
An independent clause expresses a complete thought with a subject and a verb. A dependent clause may also contain both but cannot stand alone in its context, often because it begins with a word such as 'because' or 'although'. Read the whole sentence before deciding whether a word group is complete.
Join ideas with an appropriate boundary
Two independent clauses can be separated by a full stop or joined with a semicolon when closely related. A comma plus a coordinating conjunction, such as 'and' or 'but', can also join them. A comma alone usually creates a comma splice in formal writing. Choose the boundary according to the relationship and desired pace.
Worked example
Revise: 'The rain stopped, we left the shelter.'
Show the worked solution
- Identify two independent clauses: 'The rain stopped' and 'we left the shelter'.
- A comma alone does not provide the usual formal boundary.
- Choose a full stop, semicolon, or a comma with an appropriate conjunction.
The rain stopped, and we left the shelter.
Try it yourself
Which is a complete sentence?
Common mistakes
- Sentence length alone does not determine whether a sentence is complete.
What can you explain now?
Repair 'I packed my books, the bus arrived' using a semicolon.
Compare with the explanation
I packed my books; the bus arrived.
Both sides are independent clauses. A semicolon can connect these closely related statements without a coordinating conjunction.
After trying it yourself, choose your next review. This is your self-assessment.
Your review choice appears on Today. Sign in to sync it across devices.
Original StudyForA content. AI-assisted checks completed; subject-teacher review is still pending. These lessons are not endorsed by an exam board.
Common Core English language arts standards ↗