| Supporting information: direction of flow; types of boiler; location of radiators; radiator tubes Paragraph breaks: The paragraph breaks mark stages in the process | model answer: The two graphs show that oil was the major energy source in the USA in both 1980 and 1990 and that coal, natural gas and hydroelectric power remained in much the same proportions |
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| The two graphs show the main sources of energy in the USA in the 1980s and the 1990s | You should write at least 150 words |
The hot water is then pumped round the house through a system of pipes and flows into the radiators, located in different rooms.
19| Write at least 150 words | Linkers: and, from there, then, once, again Reference words: it, both, there, which, this Topic vocabulary: enters, stored, roof, flows, ground floor, located, passes, pumped, system, circulates, heat, directed, returned, re-heated Less common vocabulary: ensure, fuelled by, heats up, distribute the heat, warms Structures: An appropriate mix of active and passive structures and a range of sentence types are used |
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| model answer: This diagram provides an overview of a domestic central heating system |
The cold water enters the house and is stored in a water storage tank in the roof.
10| The water circulates through the radiators, which have small tubes inside them to help distribute the heat, and this warms each of the rooms | Write a report for a university lecturer describing the changes which occurred |
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| Key features: Entry of cold water into boiler; circulation of hot waterto radiators and taps; return of waterto boiler |