Problem: Please answer a question about the following article about Mexico City:
Diaz's plans called for the entire city to eventually be modernized or rebuilt in the Porfirian/French style of the Colonia Roma; but the Mexican Revolution began soon afterward and the plans never came to fruition, with many projects being left half-completed. One of the best examples of this is the Monument to the Mexican Revolution. Originally the monument was to be the main dome of Diaz's new senate hall, but when the revolution erupted only the dome of the senate hall and its supporting pillars were completed, this was subsequently seen as a symbol by many Mexicans that the Porfirian era was over once and for all and as such, it was turned into a monument to victory over Diaz.
Why wasn't Diaz's plan completed? 
A: the Mexican Revolution
Problem: Please answer a question about the following article about Josip Broz Tito:
Yugoslavia had a liberal travel policy permitting foreigners to freely travel through the country and its citizens to travel worldwide, whereas it was limited by most Communist countries. A number[quantify] of Yugoslav citizens worked throughout Western Europe. Tito met many world leaders during his rule, such as Soviet rulers Joseph Stalin, Nikita Khrushchev and Leonid Brezhnev; Egypt's Gamal Abdel Nasser, Indian politicians Jawaharlal Nehru and Indira Gandhi; British Prime Ministers Winston Churchill, James Callaghan and Margaret Thatcher; U.S. Presidents Dwight D. Eisenhower, John F. Kennedy, Richard Nixon, Gerald Ford and Jimmy Carter; other political leaders, dignitaries and heads of state that Tito met at least once in his lifetime included Che Guevara, Fidel Castro, Yasser Arafat, Willy Brandt, Helmut Schmidt, Georges Pompidou, Queen Elizabeth II, Hua Guofeng, Kim Il Sung, Sukarno, Sheikh Mujibur Rahman, Suharto, Idi Amin, Haile Selassie, Kenneth Kaunda, Gaddafi, Erich Honecker, Nicolae Ceaușescu, János Kádár and Urho Kekkonen. He also met numerous celebrities.
Eisenhower was a president of what country?
A: U.S.
Problem: Please answer a question about the following article about Solar energy:
The common features of passive solar architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and thermal mass. When these features are tailored to the local climate and environment they can produce well-lit spaces that stay in a comfortable temperature range. Socrates' Megaron House is a classic example of passive solar design. The most recent approaches to solar design use computer modeling tying together solar lighting, heating and ventilation systems in an integrated solar design package. Active solar equipment such as pumps, fans and switchable windows can complement passive design and improve system performance.
What is produced when the features of passive solar architecture are customized to the environment?
A: well-lit spaces that stay in a comfortable temperature range
Problem: Please answer a question about the following article about Muslim world:
Between the 8th and 18th centuries, the use of glazed ceramics was prevalent in Islamic art, usually assuming the form of elaborate pottery. Tin-opacified glazing was one of the earliest new technologies developed by the Islamic potters. The first Islamic opaque glazes can be found as blue-painted ware in Basra, dating to around the 8th century. Another contribution was the development of stone-paste ceramics, originating from 9th century Iraq. Other centers for innovative ceramic pottery in the Old world included Fustat (from 975 to 1075), Damascus (from 1100 to around 1600) and Tabriz (from 1470 to 1550).
Around when were the first opaque glazes developed?
A:
8th century