This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Q: Passage: It is also known as the Wenchuan earthquake (Chinese: 汶川大地震; pinyin: Wènchuān dà dìzhèn; literally: "Great Wenchuan earthquake"), after the location of the earthquake's epicenter, Wenchuan County, Sichuan. The epicenter was 80 kilometres (50 mi) west-northwest of Chengdu, the provincial capital, with a focal depth of 19 km (12 mi). The earthquake was also felt in nearby countries and as far away as both Beijing and Shanghai—1,500 km (930 mi) and 1,700 km (1,060 mi) away—where office buildings swayed with the tremor. Strong aftershocks, some exceeding magnitude 6, continued to hit the area even months after the main quake, causing new casualties and damage. Question: Where was the epicenter of the earthquake?

A: Wenchuan County, Sichuan
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Q: Passage: AA gunnery was a difficult business. The problem was of successfully aiming a shell to burst close to its target's future position, with various factors affecting the shells' predicted trajectory. This was called deflection gun-laying, 'off-set' angles for range and elevation were set on the gunsight and updated as their target moved. In this method when the sights were on the target, the barrel was pointed at the target's future position. Range and height of the target determined fuse length. The difficulties increased as aircraft performance improved. Question: What was the problem with AA gunnery?

A: successfully aiming a shell to burst close to its target's future position
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Q: Passage: Timber was the chief building material during the Han dynasty; it was used to build palace halls, multi-story residential towers and halls and single-story houses. Because wood decays rapidly, the only remaining evidence of Han wooden architecture is a collection of scattered ceramic roof tiles. The oldest surviving wooden halls in China date to the Tang dynasty (618–907 AD). Architectural historian Robert L. Thorp points out the scarcity of Han-era archaeological remains, and claims that often unreliable Han-era literary and artistic sources are used by historians for clues about lost Han architecture. Question: What building material was used primarily during the Han dynasty?

A:
Timber
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