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.

Input: Consider Input: Solar distillation can be used to make saline or brackish water potable. The first recorded instance of this was by 16th-century Arab alchemists. A large-scale solar distillation project was first constructed in 1872 in the Chilean mining town of Las Salinas. The plant, which had solar collection area of 4,700 m2 (51,000 sq ft), could produce up to 22,700 L (5,000 imp gal; 6,000 US gal) per day and operate for 40 years. Individual still designs include single-slope, double-slope (or greenhouse type), vertical, conical, inverted absorber, multi-wick, and multiple effect. These stills can operate in passive, active, or hybrid modes. Double-slope stills are the most economical for decentralized domestic purposes, while active multiple effect units are more suitable for large-scale applications.

Output: In what year was a large scale solar distillation project constructed in Las Salinas?


Input: Consider Input: From the years 1500 to 1850, an estimated 3.5 million captives were forcibly shipped from West/Central Africa to Brazil; the territory received the highest number of slaves of any country in the Americas. Scholars estimate that more than half of the Brazilian population is at least in part descended from these individuals. Brazil has the largest population of Afro-descendants outside of Africa. In contrast to the US, during the slavery period and after, the Portuguese colonial government and later Brazilian government did not pass formal anti-miscegenation or segregation laws. As in other Latin countries, intermarriage was prevalent during the colonial period and continued afterward. In addition, people of mixed race (pardo) often tended to marry white, and their descendants became accepted as white. As a result, some of the European descended population also has West African or Amerindian blood. According to the last census of the 20th century, in which Brazilians could choose from five color/ethnic categories with which they identified, 54% of individuals identified as white, 6.2% identified as black, and 39.5% identified as pardo (brown) — a broad multi-racial category, including tri-racial persons.

Output: How many slaves were shipped from Africa to Brazil between 1500 and 1850?


Input: Consider Input: In contrast, Europe has a greater history of unitary states than North America, thus European "federalism" argues for a weaker central government, relative to a unitary state. The modern American usage of the word is much closer to the European sense. As the power of the Federal government has increased, some people have perceived a much more unitary state than they believe the Founding Fathers intended. Most people politically advocating "federalism" in the United States argue in favor of limiting the powers of the federal government, especially the judiciary (see Federalist Society, New Federalism).


Output: Who has a greater history of unitary states?