Band 7.5 IELTS Writing Task 1 Model Answer

Overall Band Score: 7.5 · Cambridge IELTS 19 · 2026-09-13

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 7.5)

The diagram illustrates the process of producing ethanol, a type of biofuel, from plant material and shows how carbon dioxide circulates throughout the system.

Overall, ethanol production is a cyclical process that begins with the growth of plants and trees and ends with the use of ethanol as a fuel. Carbon dioxide released during fuel consumption is absorbed by plants, creating a continuous cycle.

Initially, plants and trees grow by using energy from sunlight together with carbon dioxide from the atmosphere. Once the crops have matured, they are harvested and sent for pre-processing, where the raw plant material is prepared for the next stage. During this step, some carbon dioxide is released into the air.

Following pre-processing, cellulose is extracted from the biomass and transferred to a processing facility. There, the cellulose is converted into sugars. Microorganisms are then added to these sugars, resulting in the production of ethanol.

In the final stage, the ethanol is used as a fuel for various forms of transport, including cars, trucks and aircraft. As ethanol is burned, carbon dioxide is emitted. This gas then returns to the atmosphere and is subsequently absorbed by growing plants and trees, thereby completing the cycle of biofuel production.

AI examiner evaluation

Task Achievement / Task Response — Band 7.5

The response fully addresses all parts of the task by accurately summarising the main features of the ethanol production process and highlighting key comparisons and relationships. The student correctly identifies the cyclical nature of the process, noting both the industrial stages and the circulation of carbon dioxide in the atmosphere. The overview is clear and well-integrated, providing a strong summary of the entire diagram without missing essential details. Examples such as 'ethanol production is a cyclical process that begins with the growth of plants and trees and ends with the use of ethanol as a fuel' demonstrate a comprehensive understanding of the prompt. All steps from initial plant growth and pre-processing to cellulose extraction and final fuel consumption are reported accurately. Therefore, this performance meets the requirements for a high band.

Coherence and Cohesion — Band 7.5

The response is logically sequenced with a clear overall progression from the beginning to the end of the biofuel lifecycle. Information and ideas are presented in a coherent manner, guided by appropriate cohesive devices such as 'Initially', 'Once', 'Following pre-processing', and 'In the final stage'. Paragraphing is used effectively, with a logical division between the introduction, overview, and the sequential steps of the diagram. Referencing is clear throughout, ensuring the reader can easily follow the cycle of carbon dioxide and plant material. There is no faulty or mechanical cohesion, and the relationships between different stages are well managed. This meets the criteria for Band 8.

Lexical Resource — Band 7.5

The student demonstrates a wide and flexible lexical range suitable for an academic task. Less common vocabulary items and subject-specific terms are used accurately and naturally, such as 'cyclical process', 'pre-processing', 'cellulose', 'biomass', and 'microorganisms'. Collocations are well handled, for example, 'carbon dioxide circulates throughout the system' and 'absorbed by growing plants'. There are no significant spelling or word-choice errors, and the vocabulary allows for precise description of the technical process shown in the diagram. This strong lexical control warrants a Band 8.

Grammatical Range and Accuracy — Band 7.5

The response exhibits a wide range of complex grammatical structures used with a high degree of accuracy. The majority of sentences are error-free, featuring sophisticated subordinate clauses and participial phrases, such as 'Once the crops have matured, they are harvested and sent for pre-processing, where the raw plant material is prepared for the next stage' and 'As ethanol is burned, carbon dioxide is emitted.' Control over tense and punctuation is consistent throughout the text. Only very occasional minor slips might occur, but grammar never impedes communication. This performance aligns comfortably with the Band 8 descriptors.

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