A complex sentence joins a main clause with a clause that depends on it. It is accurate when the main clause can stand alone and the joining word matches the relationship between the two ideas.
This lesson is part of grammar repair. The same linking skill helps with topic sentences and transitions in guided writing.
How do you test a sentence for a main clause?
Find the subject and its verb. Ask whether that group of words makes sense alone, without starting with a joining word such as because, although, when, if or which.
“Although the tickets were expensive” fails: it opens with “Although”. “We bought them” passes: it stands alone. Join them: “Although the tickets were expensive, we bought them.”
Worked example: three rewrites
Here are three pairs of short, choppy sentences a student might write. All are original.
- “The bus was late. We missed the quiz.” becomes “Because the bus was late, we missed the quiz.” The link is cause and result.
- “The hall was small. It held two hundred people.” becomes “Although the hall was small, it held two hundred people.” The link is contrast.
- “Siti wrote the report. She is the class monitor.” becomes “Siti, who is the class monitor, wrote the report.” The link adds extra information about Siti.
Each rewrite keeps one main clause and adds a clause that depends on it. Read each aloud to check that the joining word matches the meaning.
The mistake: fragments and comma splices
A student might write: “Because the bus was late.” and stop. The idea is unfinished, so the reader waits for the result. Another student writes: “The bus was late, we missed the quiz.” Two complete clauses are joined by a comma alone.
| Error | Faulty | Repair |
|---|---|---|
| Fragment | Because the bus was late. | Because the bus was late, we missed the quiz. |
| Comma splice | The bus was late, we missed the quiz. | The bus was late, so we missed the quiz. |
The fix is the same each time: count the main clauses, then join them with the right joining word.
Which joining word fits which relationship?
Choose the word from the meaning, not from habit.
- Cause: because, since, as
- Contrast: although, even though, whereas
- Time: when, after, before, while
- Extra detail: who, which, whose
Never use “although” and “but” in the same sentence. “Although it rained, but we played” is wrong, because “although” already carries the contrast.
Check yourself
Repair each item. (1) “Even though he studied hard.” (2) “The tickets sold out, we queued for an hour.” (3) “Although she was tired, but she finished the essay.”
Answer
(1) “Even though he studied hard, he found the paper difficult.” The fragment needed a main clause.
(2) “The tickets sold out, so we queued for an hour.” Or use a semicolon, or a full stop between two sentences.
(3) “Although she was tired, she finished the essay.” Delete “but”, because “although” already shows the contrast.
What to study next
Continue with using conditionals to express meaning, which uses “if” clauses in the same way. Check your own paragraphs with the English writing task checklist.
For a teacher to rebuild your sentences with you, see online one-to-one English tuition.