This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Q: The materialist view is perhaps best understood in its opposition to the doctrines of immaterial substance applied to the mind historically, famously by René Descartes. However, by itself materialism says nothing about how material substance should be characterized. In practice, it is frequently assimilated to one variety of physicalism or another.

A: Was René Descartes an idealist or a materialist?
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Q: In times past, until the 15th century, in Korea, Literary Chinese was the dominant form of written communication, prior to the creation of hangul, the Korean alphabet. Much of the vocabulary, especially in the realms of science and sociology, comes directly from Chinese, comparable to Latin or Greek root words in European languages. However, due to the lack of tones in Korean,[citation needed] as the words were imported from Chinese, many dissimilar characters took on identical sounds, and subsequently identical spelling in hangul.[citation needed] Chinese characters are sometimes used to this day for either clarification in a practical manner, or to give a distinguished appearance, as knowledge of Chinese characters is considered a high class attribute and an indispensable part of a classical education.[citation needed] It is also observed that the preference for Chinese characters is treated as being conservative and Confucian.

A: What was the dominant form of written communication?
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Q: Greater London encompasses a total area of 1,583 square kilometres (611 sq mi), an area which had a population of 7,172,036 in 2001 and a population density of 4,542 inhabitants per square kilometre (11,760/sq mi). The extended area known as the London Metropolitan Region or the London Metropolitan Agglomeration, comprises a total area of 8,382 square kilometres (3,236 sq mi) has a population of 13,709,000 and a population density of 1,510 inhabitants per square kilometre (3,900/sq mi). Modern London stands on the Thames, its primary geographical feature, a navigable river which crosses the city from the south-west to the east. The Thames Valley is a floodplain surrounded by gently rolling hills including Parliament Hill, Addington Hills, and Primrose Hill. The Thames was once a much broader, shallower river with extensive marshlands; at high tide, its shores reached five times their present width.

A:
In the past, how much wider was the River Thames than it is today?
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