Band 8.5 IELTS Writing Task 1 Model Answer

Overall Band Score: 8.5 · Cambridge IELTS 19 · 2026-09-16

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 8.5)

The process diagram illustrates the procedure for producing biofuel, or ethanol.

Overall, the process begins with the cultivation of plants, which use sunlight and carbon dioxide to grow, and ends with the production and use of ethanol as a fuel. The process is cyclical, as carbon dioxide released by vehicles is subsequently absorbed by plants during their growth.

Initially, plants are cultivated on a large scale, using sunlight and carbon dioxide to grow. Once they have reached maturity, the plants are harvested and transported to a factory. There, a specialised machine extracts the raw material from the harvested plants, which is then processed to produce cellulose. The cellulose subsequently undergoes further processing to produce sugar.

In the next stage, microbes are added to the sugar in order to produce ethanol. The resulting biofuel is then made available for vehicles. Cars, trucks and aeroplanes use ethanol as fuel and release carbon dioxide into the atmosphere. This carbon dioxide is then absorbed by newly growing plants, thereby completing the cycle.

AI examiner evaluation

Task Achievement / Task Response — Band 8.0

The student successfully addresses all parts of the task by providing a clear and comprehensive summary of the process diagram showing how ethanol is produced. The response effectively highlights the main features, such as the initial cultivation of plants, harvesting, pre-processing into cellulose, processing into sugars, adding microbes to create ethanol, and the subsequent release and reabsorption of carbon dioxide. An appropriate and clear overview is provided in the second paragraph, correctly identifying both the linear progression of biofuel production and its cyclical nature. All stages depicted in the source diagram are reported accurately without any omissions or significant misinterpretations, demonstrating a strong understanding of the visual data.

Coherence and Cohesion — Band 8.5

The response is logically sequenced and easy to follow, with a clear progression from the beginning to the end of the biofuel production cycle. Information and ideas are structured effectively into well-managed paragraphs that separate the introduction and overview from the detailed body stages. Cohesive devices are used naturally and appropriately to guide the reader through the sequence, utilizing transition words such as 'Overall', 'Initially', 'Once', 'There', and 'In the next stage'. Paragraphing is used sufficiently and appropriately, and referential pronouns (such as 'which', 'This') are managed skillfully without ambiguity.

Lexical Resource — Band 8.0

The student demonstrates a wide, fluent, and flexible range of vocabulary suitable for describing a technical or scientific process. Less common items and appropriate process-related terminology are used skillfully, including words and phrases like 'cultivation', 'maturity', 'specialised machine', 'cellulose', and 'atmospheric'. Word choice and collocations are generally very accurate, with only rare minor instances of phrasing that could be further refined. Spelling and word formation are entirely correct throughout the response, allowing the reader to comprehend the technical information smoothly and effortlessly.

Grammatical Range and Accuracy — Band 8.5

The response displays a wide variety of complex sentence structures used with a high degree of accuracy. The majority of sentences are completely error-free, showcasing complex clauses such as 'which use sunlight and carbon dioxide to grow', 'Once they have reached maturity, the plants are harvested...', and 'which is then processed to produce cellulose.' Control of grammar, tense consistency (predominantly present simple for general processes), and punctuation is excellent. Only very occasional minor slips might occur, but none impede communication or detract from the overall high standard of grammatical control.

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