Writing: B1 - Lesson 2: Writing a Clear Topic Sentence

Writing: Building Strong Paragraphs

B1 Lesson 2: Writing a Clear Topic Sentence

Listen to the lesson concepts here.

What you will learn: By the end of this lesson, you will be able to identify the two parts of a good topic sentence and write a clear topic sentence that tells your reader the main idea of your paragraph.

Before You Start 🧠

Key Vocabulary (Click 🔊)

Let's learn these important words for this lesson.

Topic Sentence

| ប្រយោគប្រធានបទ

The most important sentence in a paragraph. It tells the main idea.

Topic

| ប្រធានបទ

The general subject of the paragraph (e.g., "smartphones").

Controlling Idea

| គំនិតគ្រប់គ្រង

Your specific opinion or point about the topic (e.g., "...are useful for students").

Supporting Details

| ព័ត៌មានលម្អិតគាំទ្រ

The other sentences in the paragraph that give examples or reasons.

What is a Topic Sentence?

A topic sentence is the "boss" of the paragraph. It's usually the first sentence, and it gives the reader two key pieces of information:

1. What is the paragraph about? (The Topic)
2. What is your main point about that topic? (The Controlling Idea)

Think of it as a signpost: it tells the reader where the paragraph is going.

The Two-Part Formula

TOPIC + CONTROLLING IDEA = A Good Topic Sentence

"Studying in Siem Reap has three main advantages."

TOPIC: "Studying in Siem Reap"

CONTROLLING IDEA: "has three main advantages"

After this sentence, the reader expects the paragraph to list the three advantages. It's a clear map!

Examples: Good vs. Bad Topic Sentences

❌ TOO GENERAL (Vague)

"Cambodia is an interesting country."

Why it's bad: "Interesting" is too vague. The paragraph could be about food, history, or traffic. The reader doesn't know the main point.

❌ TOO SPECIFIC (A Fact)

"Angkor Wat was built in the 12th century."

Why it's bad: This is just a fact. There is nothing left to say. The paragraph has no direction and ends immediately.

✅ GOOD (Just Right)

"Visiting Angkor Wat is an unforgettable experience for tourists."

Why it's good:
Topic: "Visiting Angkor Wat"
Controlling Idea: "is an unforgettable experience"

✅ GOOD (Just Right)

"Social media has a negative impact on young people's mental health."

Why it's good:
Topic: "Social media"
Controlling Idea: "has a negative impact on mental health"

Practice What You Learned 🎯

Quiz: Which is the BEST Topic Sentence?

Read the questions below. Choose the best topic sentence that is not too general and not too specific. Click "Check Answers" when done.

1. Which sentence is TOO GENERAL?

• A) Khmer food is delicious.
• B) Food is good.
• C) My favorite Khmer dish is Fish Amok.

2. Which sentence is TOO SPECIFIC (a fact)?

• A) Traveling in Cambodia is a great experience.
• B) The bus from Phnom Penh to Siem Reap takes 6 hours.
• C) Traveling by bus in Cambodia is often unreliable.

3. Which is the BEST topic sentence for a paragraph?

• A) Exercise is important.
• B) Exercising in the morning has several benefits for your day.
• C) I went to the gym at 6 AM today.

Key Vocabulary Reference (Click 🔊)

• Topic Sentence | ប្រយោគប្រធានបទ
  The main sentence of a paragraph; it states the topic and the controlling idea.
• Topic | ប្រធានបទ
  The general subject of the paragraph (e.g., "smartphones", "Khmer food").
• Controlling Idea | គំនិតគ្រប់គ្រង
  Your specific point, opinion, or focus about the topic (e.g., "...are expensive", "...is delicious").
• Supporting Details | ព័ត៌មានលម្អិតគាំទ្រ
  Sentences that give examples, reasons, or facts to prove the topic sentence.

Your Writing Mission ⭐

Practice Writing Topic Sentences

Your mission is to practice writing clear topic sentences. Choose two (2) of the topics below and write one good topic sentence for each.

Remember the formula: TOPIC + CONTROLLING IDEA.

• My favorite food
• Learning English
• My smartphone
• Traffic in my city

Example Topic: "My favorite food"
Example Topic Sentence: "My favorite food is Kuy Teav because it is delicious and easy to find in the morning."

Share your sentences in the comments section!