Paragraph Structure: Topic Sentence, Support, Conclusion
B1 · Writing Lab · about 30 minutes
1 · Learn
At B1, the paragraph becomes your main unit of writing. Its anatomy is fixed: the topic sentence carries a topic PLUS a controlling idea (“Working from home saves time and energy” — the idea is not “working from home”, it is the saving). Everything after it must develop that controlling idea.
Strong support comes in layers: a reason (why), an example (a case the reader can see), and a detail (a number, a time, a name). Weak paragraphs repeat the topic sentence in new words; strong ones keep adding evidence.
2 · See an Example
Anatomy of a Strong Paragraph
Learning a language as an adult is slower than as a child, but it is far more efficient. Adults understand grammar explanations and can connect new words to a lifetime of knowledge. For example, a doctor learning English medical terms already knows what the words must mean, so she memorizes them twice as fast as a teenager. Adults also choose their own reasons — a job, a move, a relationship — and real reasons produce real discipline. The child learns by accident; the adult learns on purpose, and purpose is a powerful teacher.
3 · Analyze the Example
- Topic + controlling idea. Not just “adult learning” — the claim is “slower but more efficient”. Every sentence must serve the efficiency claim.
- Reason layer. Adults understand explanations and connect words to knowledge — the why behind the claim.
- Example layer. The doctor makes the claim visible: prior knowledge doubles her speed.
- Concluding sentence with a twist. “The child learns by accident; the adult learns on purpose” — a conclusion that reframes, not repeats.
Useful Vocabulary
“Saves money” is the controlling idea in “Cycling saves money.”
This method is more efficient.
Support your opinion with an example.
He learns on purpose, not by accident.
She memorizes ten words a day.
Useful Expressions
- … is not just …; it is …
- For example, …
- In fact, …
- As a result, …
- In other words, …
Common Mistakes
✗ Exercise is good. Exercise is healthy. Many people exercise. Exercise is important for everyone.
✓ Daily exercise protects the heart more effectively than any supplement. Studies show that thirty minutes of walking cuts the risk of heart disease, because it strengthens the heart muscle and lowers blood pressure over time.
The first version circles the topic without a controlling idea or evidence. The second commits to a claim and supports it.
✗ Topic sentence: “There are many kinds of music in the world.” Then a paragraph about why jazz is relaxing.
✓ Topic sentence: “Jazz is the most relaxing music to work to.” Then support about jazz.
The topic sentence must promise exactly what the paragraph delivers — no wider, no narrower.
✗ Conclusion: “In conclusion, as I said, exercise is good, like I wrote above.”
✓ Conclusion: “The adult learns on purpose — and purpose is a powerful teacher.”
A conclusion that announces itself and repeats the text wastes the strongest line in the paragraph.
4 · Guided Practice
Find the controlling idea: “City buses should be free for students because transport costs decide who can study.”
See a model answer
Topic: free buses for students. Controlling idea: costs decide who can study — the paragraph must argue access, not buses in general.
Add an example layer to this reason: “Home cooking is cheaper because restaurants charge for service and rent.”
See a model answer
Example: “A pasta dinner for four costs about $12 at home and over $60 in a restaurant.”
Choose the stronger conclusion: (a) “So, in conclusion, that is my paragraph about libraries.” (b) “A library card is the cheapest university in the world.”
See a model answer
(b) — it reframes the idea memorably instead of announcing the ending.
5 · Write — Your Task
✍️ Write ONE strong paragraph (120–150 words) on a claim you believe: learning online, living with family as an adult, social media for teenagers, or your own topic. Build it with a controlling topic sentence, a reason, an example with a concrete detail, and a concluding sentence that reframes the idea.
Goal: 1 paragraph, 7–9 sentences · Length: 120–150 words
- Write the topic sentence twice: first the topic, then add the controlling idea.
- Give the example a number, a name, or a time — concrete beats general.
- Save your cleverest line for the conclusion.
6 · Check — Self-Check
Work through your checklist honestly, then run the Self-Check. It counts words and sentences and spots mechanical points — it does not grade your English. You are the editor.
Read a model answer for the task
A small town is a better place to raise children than a big city, not because it is prettier, but because it is safer in the ways that matter daily. Children can walk to school with friends instead of sitting in traffic, and neighbors know whose child is whose. For example, in my town, when my nephew fell off his bike last spring, three different adults helped him before his mother even heard about it. That invisible safety net is something no city apartment, however modern, can buy.
7 · Improve & Rewrite
Weak version — rewrite it in your notebook first, then compare:
Social media is popular. Many people use social media every day. It is good and bad. People like it a lot. In conclusion, social media is something people use.
See an improved version
Social media has quietly changed how friendships work, replacing long conversations with quick reactions. A “like” takes one second, so many people now collect hundreds of shallow contacts instead of keeping five real friends. For example, my cousin has 900 followers but called nobody when she lost her job. The technology connects everyone — and somehow leaves people lonelier than before.
Quick Quiz
Keep going
📘 Grammar deep-dive: Sentence Structure & Word Order: SVOMPT🌱 Vocabulary Builder: the B1 Learning Goals set🎓 TOEFL Writing: the exam version of this skillB1 — all lessons · Next: Personal Emails That Sound Natural →
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