Learn about sentence boundaries, punctuation, commas, semicolons, and run-ons. Practice with 10 solved questions.
🎯 What You'll Learn
• How to identify complete and incomplete sentences
• How to use commas, semicolons, and periods correctly
• How to fix run-on sentences and comma splices
• How to use punctuation to clarify meaning
📖 What Are Boundaries?
Boundary questions test your ability to identify where one sentence ends and another begins, and how to use punctuation correctly to separate ideas. Common issues include:
Run-on sentences: Two or more complete sentences joined without proper punctuation
Comma splices: Two complete sentences joined only by a comma
Sentence fragments: Incomplete sentences that are missing a subject or verb
Incorrect punctuation: Using commas, semicolons, or colons incorrectly
Punctuation Rules
Punctuation
Use
Example
Period (.)
Ends a complete sentence
I went to the store. I bought milk.
Semicolon (;)
Joins two related complete sentences
I went to the store; I bought milk.
Comma + conjunction ( , and )
Joins two complete sentences
I went to the store, and I bought milk.
Comma (,)
Separates items in a list or clauses
I bought milk, eggs, and bread.
Colon (:)
Introduces a list or explanation
I bought three items: milk, eggs, and bread.
💡 Key Strategy
To check if a sentence is complete, look for a subject (who or what) and a verb (action). If both are present and it expresses a complete thought, it's a complete sentence.
⚡ 3-Step Boundary Strategy
STEP 1
Identify the Clauses
How many complete sentences are there?
STEP 2
Check the Relationship
How are the clauses related?
STEP 3
Choose Correct Punctuation
What punctuation best separates or connects them?
🧪 Practice Questions
Read each sentence and choose the option that correctly punctuates the sentence. Click "Show Answer" for explanations.
Question 1
She wanted to go to the concert ____ she didn't have enough money for the ticket.
Which option correctly completes the sentence?
A) ,
B) , but
C) ; however,
D) ;
✓ Answer: B
Two complete sentences are joined with a comma + conjunction (but). The comma alone (A) would be a comma splice. Semicolon alone (D) would be correct but doesn't show contrast. "; however," would be correct but requires different wording.
📝 Rule: Comma + conjunction joins two complete sentences with contrast.
Question 2
The restaurant was crowded ____ we decided to eat somewhere else.
Which option correctly completes the sentence?
A) ,
B) ;
C) , so
D) :
✓ Answer: C
Two complete sentences with a cause-effect relationship. The second clause is a result of the first. "So" shows this relationship with a comma.
📝 Rule: Comma + so joins two sentences with cause-effect.
Question 3
I need to buy several things at the store ____ milk, eggs, and bread.
Which option correctly completes the sentence?
A) ,
B) ;
C) , and
D) :
✓ Answer: D
A colon introduces a list. The first part is a complete sentence that sets up the list, and the colon signals that a list follows.
📝 Rule: Colon introduces a list after a complete sentence.
Question 4
The students finished their project ____ they submitted it to the teacher.
Which option correctly completes the sentence?
A) ,
B) , and
C) , but
D) ; however,
✓ Answer: B
Two complete sentences that show sequence. "And" connects them with a comma. The actions are related and in order.
📝 Rule: Comma + and joins two related complete sentences.
Question 5
The book was long ____ it was surprisingly easy to read.
Which option correctly completes the sentence?
A) , but
B) , and
C) , for
D) ; therefore,
✓ Answer: A
Two complete sentences with contrast. Being long usually means it's hard to read, but here it's easy. "But" shows this contrast.
📝 Rule: Comma + but joins two sentences with contrast.
Question 6
I woke up late ____ I missed the bus.
Which option correctly completes the sentence?
A) ,
B) ; however,
C) , so
D) :
✓ Answer: C
Waking up late caused missing the bus. "So" shows this cause-effect relationship. Two complete sentences joined correctly.
📝 Rule: Comma + so shows cause-effect.
Question 7
The recipe calls for many ingredients ____ flour, sugar, eggs, and butter.
Which option correctly completes the sentence?
A) :
B) ,
C) ;
D) , and
✓ Answer: A
A colon introduces a list of items. The first part is a complete sentence that sets up the list.
📝 Rule: Colon introduces a list.
Question 8
She studied for hours ____ she still failed the exam.
Which option correctly completes the sentence?
A) ,
B) ;
C) , and
D) , but
✓ Answer: D
Despite studying, she failed. "But" shows this contrast. Two complete sentences connected correctly.
📝 Rule: Comma + but shows contrast.
Question 9
The team practiced every day ____ they won the championship.
Which option correctly completes the sentence?
A) ; consequently,
B) , but
C) , yet
D) , for
✓ Answer: A
Practicing caused winning. Semicolon + consequently shows this cause-effect relationship. Other options would also work but "consequently" is the clearest cause-effect marker.