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: Its knowledge and uses spread from China through the Middle East to medieval Europe in the 13th century, where the first water powered paper mills were built. Because of paper's introduction to the West through the city of Baghdad, it was first called bagdatikos. In the 19th century, industrial manufacture greatly lowered its cost, enabling mass exchange of information and contributing to significant cultural shifts. In 1844, the Canadian inventor Charles Fenerty and the German F. G. Keller independently developed processes for pulping wood fibres.

A: In what century did the papermaking process spread from China to Europe?
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Q: According to China daily. Fifteen years after the satellite system was launched, it is now generating $31.5 billion for major companies such as China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp.

A: How long ago was the BeiDou Satellite System first launched?
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Q: As the 10th century progressed, the Khazars were no longer able to command tribute from the Volga Bulgars, and their relationship with the Byzantines deteriorated, as Byzantium increasingly allied with the Pechenegs against them. The Pechenegs were thus secure to raid the lands of the Khazars from their base between the Volga and Don rivers, allowing them to expand to the west. Rus' relations with the Pechenegs were complex, as the groups alternately formed alliances with and against one another. The Pechenegs were nomads roaming the steppe raising livestock which they traded with the Rus' for agricultural goods and other products. The lucrative Rus' trade with the Byzantine Empire had to pass through Pecheneg-controlled territory, so the need for generally peaceful relations was essential. Nevertheless, while the Primary Chronicle reports the Pechenegs entering Rus' territory in 915 and then making peace, they were waging war with one another again in 920. Pechenegs are reported assisting the Rus' in later campaigns against the Byzantines, yet allied with the Byzantines against the Rus' at other times.

A:
Around what time did the Khazars unable to no longer command tribute from Volga?
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