Topic Explanation and Use
Core idea
Sentence control affects every writing score because the reader needs to know where one idea ends and the next one begins.
A run-on sentence happens when two complete ideas are pushed together without the right connector or punctuation. A fragment is the opposite problem: the writer stops too early and leaves an incomplete idea. Both problems make exam writing harder to follow.
The good news is that most fixes are simple. If you have two full ideas, you can separate them with a period, connect them with a comma plus a joining word such as because or but, or use a semicolon when the connection is close. If you have a fragment, add the missing subject, verb, or complete main clause.
At B2 level, the goal is not to write longer sentences. The goal is to write complete, readable sentences that hold together under time pressure.
Use it here
- Read one sentence at a time and ask: is this a full idea?
- If two full ideas appear together, choose a real connector or split them.
- Watch for dependent clauses that cannot stand alone.
Watch it work
Remember this
- One sentence needs one complete main clause at minimum.
- If you see two complete ideas, join them properly or split them.
- A comma alone cannot safely join two full sentences.
- Words like because, although, and if create dependent clauses that need a main clause.
- Short clear sentences are better than long broken ones.
Real-World Examples with Run-On Sentences and Fragments
Example 1
Too weakThe class ended late I missed my bus home.
BetterThe class ended late, so I missed my bus home.
The better sentence joins the two ideas correctly.
Example 2
Too weakBecause the office was closed on Monday.
BetterBecause the office was closed on Monday, I submitted the form on Tuesday morning.
The stronger version completes the thought.
Common Errors with Run-On Sentences and Fragments
Common problem 1
joining two full sentences with only a comma
WeakI wanted to attend the webinar, my shift ended too late.
StrongI wanted to attend the webinar, but my shift ended too late.
Fix: Add a joining word or split the sentence.
Common problem 2
leaving a dependent clause alone
WeakAlthough the manager replied quickly.
StrongAlthough the manager replied quickly, the problem was not solved until Friday.
Fix: Add the main clause that finishes the idea.
Common problem 3
stacking too many ideas into one line
WeakThe event was useful it was expensive many students still attended because they needed certificates.
StrongThe event was useful, but it was expensive. Many students still attended because they needed certificates.
Fix: Break long chains into smaller complete sentences.
Interactive Practice Lab
Practice
Spot the broken sentence, then repair it in the simplest clear way.
Score: 0/4
When in doubt, use a period. Clear is better than crowded.
1. Quick pick
Which sentence is complete and correct?
2. Build the fix
Put these editing steps in the best order.
Repair the logic before you worry about style.
3. Repair the fragment
Type the full corrected sentence.
SourceBecause the bus was late.
4. Last check
Which repair is safer for exam writing?
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