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 city uses the strong-mayor version of the mayor-council form of government, which is headed by one mayor, in whom executive authority is vested. Elected at-large, the mayor is limited to two consecutive four-year terms under the city's home rule charter, but can run for the position again after an intervening term. The Mayor is Jim Kenney, who replaced Michael Nutter, who served two terms from 2009 to January 2016. Kenney, as all Philadelphia mayors have been since 1952, is a member of the Democratic Party, which tends to dominate local politics so thoroughly that the Democratic Mayoral primary is often more widely covered than the general election. The legislative branch, the Philadelphia City Council, consists of ten council members representing individual districts and seven members elected at large. Democrats currently hold 14 seats, with Republicans representing two allotted at-large seats for the minority party, as well as the Northeast-based Tenth District. The current council president is Darrell Clarke.
[A]: What type of government does Philadelphia have?


[Q]: The Queensboro Bridge is an important piece of cantilever architecture. The Manhattan Bridge, Throgs Neck Bridge, Triborough Bridge, and Verrazano-Narrows Bridge are all examples of Structural Expressionism.
[A]: What architectural style does the Throgs Neck Bridge reflect?


[Q]: People lived on the edge of the desert thousands of years ago since the last ice age. The Sahara was then a much wetter place than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive, with half found in the Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs, including Afrovenator, Jobaria and Ouranosaurus, have also been found here. The modern Sahara, though, is not lush in vegetation, except in the Nile Valley, at a few oases, and in the northern highlands, where Mediterranean plants such as the olive tree are found to grow. It was long believed that the region had been this way since about 1600 BCE, after shifts in the Earth's axis increased temperatures and decreased precipitation. However, this theory has recently been called into dispute, when samples taken from several 7 million year old sand deposits led scientists to reconsider the timeline for desertification.
[A]:
When did people start living on the edge of the desert?