A student writes a paragraph with the topic sentence 'Dogs make great family pets.' The paragraph includes sentences about dogs' loyalty, dogs' playfulness, and a sentence about how cats are very independent animals. What is wrong?
ANothing — including more information makes a paragraph stronger.
BThe sentence about cats does not belong — it introduces a new idea unrelated to the topic sentence, breaking the paragraph's unity.
CThe topic sentence should come at the end, not the beginning.
DSupporting sentences should only state facts, not give examples.
The core rule of paragraph unity is that every sentence must relate back to the topic sentence. The sentence about cats' independence does not support 'dogs make great family pets' — it belongs in a different paragraph with its own topic sentence. Including off-topic sentences is the most common paragraph-writing error and reflects not understanding what a paragraph is: a group of sentences all about ONE main idea.
Question 2 Multiple Choice
Which of the following is the strongest topic sentence for a paragraph about the importance of eating breakfast?
A'Breakfast is a meal eaten in the morning.'
B'Some people eat breakfast and some people skip it.'
C'Eating breakfast gives your brain and body the energy they need to focus and perform well in the morning.'
D'My favorite breakfast is eggs and toast with orange juice.'
A topic sentence must make a specific, arguable claim that several supporting sentences can explain. Option A is too obvious to need explanation. Option B makes no real claim. Option D is a supporting detail, not a main idea — it's too specific to guide a whole paragraph. Option C makes a clear, focused claim about why breakfast matters, which is broad enough to need explanation but specific enough to keep the paragraph on track.
Question 3 True / False
A concluding sentence should echo the main idea of the paragraph but not simply copy the topic sentence word for word.
TTrue
FFalse
Answer: True
The concluding sentence 'closes the circle' — it reminds the reader of the main idea after all the details, but a word-for-word copy of the topic sentence feels redundant and flat. The best concluding sentences restate the idea in fresh language or explain why it matters, giving the paragraph a sense of completion rather than just repetition.
Question 4 True / False
A paragraph can cover several different topics, as long as most of the sentences are long and detailed.
TTrue
FFalse
Answer: False
Length and detail do not make a paragraph — unity does. A paragraph is defined by having one main idea that all its sentences support. A collection of long, detailed sentences about unrelated topics is not a paragraph; it is unorganized writing. The moment a new idea needs to be developed, a new paragraph must begin.
Question 5 Short Answer
What is the job of a topic sentence, and what makes one 'just right'?
Think about your answer, then reveal below.
Model answer: The topic sentence makes a promise to the reader: it states the one main idea that every other sentence in the paragraph will support. A good topic sentence is specific enough to guide the supporting details — not so broad that anything could follow it — but broad enough that it takes several sentences to explain fully. It should make a claim or observation worth proving, not state something too obvious or too narrow.
Thinking of the topic sentence as a 'promise' is the key insight. Students who write generic openers ('Dogs are animals') set no real direction for the paragraph. When students understand that the topic sentence defines the boundaries for everything that follows, they naturally evaluate each supporting sentence by asking: 'Does this keep my promise?'