Complete sentences and boundaries
Locate independent and dependent clauses before deciding where a sentence can end or how clauses may join.
What you will tackle
- Recognise finite independent clauses and dependent fragments
- Correct run-ons and comma splices
- Use sentence endings, semicolons and comma-plus-coordinator boundaries
A complete clause needs a finite verb
‘The archive preserves local maps’ is independent. ‘Because the archive preserves local maps’ is dependent: because creates an expectation of a main clause. A participial phrase such as ‘Preserving local maps’ does not by itself make a complete sentence.
Choose a grammatical relationship
Two independent clauses can be separate sentences, joined with a semicolon, or joined with a comma and a coordinating conjunction. A comma alone is a splice. Do not use a semicolon to separate a dependent clause from the main clause it completes.
Build your notes, then practise
Work on paper before opening an explanation. Guided tasks provide a starting point; independent tasks remove the scaffolding; application tasks ask you to justify a method or interpretation in context.
Guided practice
Guided 1
Repair ‘The storm ended, the researchers resumed work’ in three ways. Is ‘Because the storm ended’ a complete sentence?
Show a starting hint
Test each side as a sentence by itself.
Compare with the explained answer
- Both original clauses are independent, so a comma alone is insufficient.
- Use a period, a semicolon, or ‘, and’ between them.
- Because makes the final phrase dependent; it needs a main clause.
Answer / response criteria: ‘The storm ended. The researchers resumed work.’ ‘The storm ended; the researchers resumed work.’ ‘The storm ended, and the researchers resumed work.’ The because-clause is incomplete alone.
Independent practice
Independent 1
Choose the grammatical version and explain: A ‘The samples drying overnight.’ B ‘The samples dried overnight.’ C ‘Although the samples dried overnight.’
Compare with the explained answer
- A has a participle but no finite main verb.
- B has subject samples and finite verb dried.
- C is a dependent clause introduced by although.
Answer / response criteria: B is the complete independent sentence.
Application practice
Application 1
Revise ‘The route was short however it crossed a busy road’ to preserve the contrast without a run-on. Then add a dependent clause explaining why the group took extra care.
Compare with the explained answer
- However cannot join independent clauses by itself.
- Write ‘The route was short; however, it crossed a busy road.’
- A valid addition is ‘Because traffic was heavy, the group took extra care.’
Answer / response criteria: ‘The route was short; however, it crossed a busy road. Because traffic was heavy, the group took extra care.’
What can you explain now?
Revise ‘The route was short however it crossed a busy road’ to preserve the contrast without a run-on. Then add a dependent clause explaining why the group took extra care.
Compare with the explanation
‘The route was short; however, it crossed a busy road. Because traffic was heavy, the group took extra care.’
Explain the reasoning before comparing. This review records your self-assessment rather than an official score or mastery decision.
After trying it yourself, choose your next review. This is your self-assessment.
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Source and review status
Coverage follows the named requirements and examples in the 2026–2027 ACT test guide and subject descriptions. That guide explicitly does not list every possible topic. The broader coded College and Career Readiness Standards are also mapped to conceptual teaching and practice; this does not calibrate a learner to a score band. The separate scientific-background context list and reading-complexity rubric have their own stated limits.
Original teaching and explained self-check practice are available. Specialist review and difficulty calibration remain pending. Essays require self-check or teacher review and are not automatically marked or awarded official scores.
Official source specification / guide