Paragraph Structure

A paragraph is the basic organisational unit of written discourse. In academic and formal writing, a well-constructed paragraph develops a single main idea through a predictable internal structure: topic sentence, supporting sentences, and (optionally) a concluding sentence.

Core Components

Topic Sentence

The Topic Sentence states the paragraph's main idea and controls its scope. It typically appears first, orienting the reader to what follows. Everything in the paragraph should connect to and develop this controlling idea.

Supporting Sentences

Supporting sentences develop the topic sentence through:

• Explanation — Clarifying the main idea
• Evidence — Facts, statistics, research findings
• Examples — Specific instances that illustrate the point
• Detail — Descriptive or narrative elaboration
• Reasoning — Logical argument connecting evidence to claim

Concluding Sentence

Optional in body paragraphs but common in academic writing. It may summarise the paragraph's point, link back to the topic sentence, or transition to the next paragraph.

Two Key Principles

Unity — A paragraph has one main idea. Every sentence must relate to and develop the topic sentence. If a sentence introduces a new main idea, it belongs in a new paragraph. Lack of unity is one of the most common weaknesses in L2 academic writing.

Coherence — Ideas flow logically from one sentence to the next. Coherence is achieved through:

• Logical ordering of ideas (general → specific, chronological, cause → effect)
• Cohesion devices (linking words, reference, substitution, lexical chains)
• Consistent topic focus (known → new information flow)

Teaching Paragraph Structure

Sequence

1. Identify — Learners read well-structured paragraphs and identify topic sentences, supporting details, and concluding sentences
2. Analyse — Examine how supporting sentences develop the topic sentence (example? explanation? evidence?)
3. Evaluate — Given paragraphs with unity problems (irrelevant sentences), learners identify and remove the off-topic material
4. Order — Jumbled sentences reassembled into a coherent paragraph
5. Complete — Given a topic sentence, write supporting sentences (or vice versa)
6. Compose — Write complete paragraphs independently

Common Student Problems

Problem	Description	Teaching response
No topic sentence	Paragraph drifts without a clear controlling idea	Practise writing topic sentences from prompts
Off-topic sentences	Supporting details unrelated to the topic sentence	Highlight-and-delete exercises
Underdeveloped	Topic sentence + one or two thin sentences	Model how to expand with PEEL (Point, Evidence, Explanation, Link)
List-like structure	Series of disconnected points	Teach Cohesion devices and logical connectors
Over-long paragraphs	Multiple ideas crammed into one block	Teach paragraph division based on shifts in main idea

Paragraph Length

There is no universal rule for paragraph length. In academic writing, 5-8 sentences is a common guideline, but the real criterion is whether the idea is fully developed. A three-sentence paragraph that makes its point effectively is better than an eight-sentence paragraph that rambles. In IELTS Writing, body paragraphs of 4-6 sentences typically provide sufficient development.