Problem: Medieval writers divided history into periods such as the "Six Ages" or the "Four Empires", and considered their time to be the last before the end of the world. When referring to their own times, they spoke of them as being "modern". In the 1330s, the humanist and poet Petrarch referred to pre-Christian times as antiqua (or "ancient") and to the Christian period as nova (or "new"). Leonardo Bruni was the first historian to use tripartite periodisation in his History of the Florentine People (1442). Bruni and later historians argued that Italy had recovered since Petrarch's time, and therefore added a third period to Petrarch's two. The "Middle Ages" first appears in Latin in 1469 as media tempestas or "middle season". In early usage, there were many variants, including medium aevum, or "middle age", first recorded in 1604, and media saecula, or "middle ages", first recorded in 1625. The alternative term "medieval" (or occasionally "mediaeval") derives from medium aevum. Tripartite periodisation became standard after the German 17th century historian Christoph Cellarius divided history into three periods: Ancient, Medieval, and Modern.
Along with the Six Ages, what other scheme did writers in the Middle Ages use to divide history?
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Answer: Four Empires

Problem: Though Houston is the largest city in the United States without formal zoning regulations, it has developed similarly to other Sun Belt cities because the city's land use regulations and legal covenants have played a similar role. Regulations include mandatory lot size for single-family houses and requirements that parking be available to tenants and customers. Such restrictions have had mixed results. Though some have blamed the city's low density, urban sprawl, and lack of pedestrian-friendliness on these policies, the city's land use has also been credited with having significant affordable housing, sparing Houston the worst effects of the 2008 real estate crisis. The city issued 42,697 building permits in 2008 and was ranked first in the list of healthiest housing markets for 2009.
How many building permits were issued in 2008 in Houston?
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Answer: 42,697

Problem: In practice, because of sovereignty, any state can withdraw from any treaty at any time. The question of whether this is permitted is really a question of how other states will react to the withdrawal; for instance, another state might impose sanctions or go to war over a treaty violation.
What really determines whether withdrawal from a treaty is permitted?
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Answer:
how other states will react