Band 4.0 IELTS Writing Task 1 Model Answer

Overall Band Score: 4.0 · Cambridge IELTS 19 · 2026-10-10

IELTS Writing Task 1 question

 

The diagram below shows how a biofuel called ethanol is produced.

Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

Student answer (Band 4.0)

The diagram shows the how ethanol is produced from plants and how to used as a biofuel.

overall, the process starts with the growth of plants and ends with the use of ethanol fuel.

firstly, plant are growth with sunlights and carbon dioxide.

AI examiner evaluation

Task Achievement / Task Response: Band 3.0

The response identifies the general subject and gives a basic start-and-end overview: it says the process begins with plant growth and ends with ethanol being used as fuel. It also correctly mentions sunlight and carbon dioxide as inputs for plant growth. However, the account stops after this first stage and omits nearly all the main features shown, including harvesting, pre-processing, cellulose, processing into sugars, the addition of microbes, and the transport uses of ethanol. It also does not explain the carbon-dioxide loop back to the plants. The response is substantially below the required 150 words, leaving the task only minimally addressed. To improve, describe the stages in sequence and include the cycle’s key inputs, outputs and uses.

Coherence and Cohesion: Band 4.5

The ideas follow a simple, understandable order: an opening identifies the diagram, an overview gives the start and end, and “firstly” introduces the first stage. This provides a basic progression, but the response ends before it can develop a complete process description, and there is no paragraphing to distinguish the overview from the stages. The linking is also limited to “overall” and “firstly,” so relationships between later steps are not shown. Build a clear sequence using connectors such as “next,” “after this,” and “finally,” and group the overview separately from the detailed stages. This would make the progression more complete and easier to follow.

Lexical Resource: Band 4.5

The response uses a few relevant terms, including “ethanol,” “biofuel,” “plants,” “sunlight,” and “carbon dioxide,” so the topic is recognisable. However, the vocabulary range is very limited and does not cover most of the diagram’s stages or outputs. Some word choices and forms are inaccurate, such as “plants are growth” and “sunlights,” which reduce naturalness. Use precise process vocabulary from the diagram, for example “harvested,” “pre-processed,” “cellulose,” “converted into sugars,” and “microbes are added.” Avoid repeating general terms when a specific stage name is available. A broader, more accurate set of process verbs and nouns would make the description clearer.

Grammatical Range and Accuracy: Band 4.5

The response mainly uses short, simple sentences, and the basic meaning is generally recoverable. However, grammatical control is inconsistent even in these short structures. In “The diagram shows the how ethanol is produced,” the article “the” is unnecessary; “how to used” has an incorrect verb form; and “plant are growth” contains errors in agreement and verb form. The sentence beginning “firstly” also needs a capital letter after the preceding full stop. There is little variety in sentence structure, so the response does not demonstrate a wider range. Practise accurate present-simple passive forms, such as “plants are grown,” and combine stages with clauses such as “After harvesting, the plants are processed to produce cellulose.”

See this exact question answered at other band scores. The same prompt compared across bands.

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