Problem: Saint Helena:

Englishman Sir Francis Drake probably located the island on the final leg of his circumnavigation of the world (15771580). Further visits by other English explorers followed, and, once Saint Helena's location was more widely known, English ships of war began to lie in wait in the area to attack Portuguese India carracks on their way home. In developing their Far East trade, the Dutch also began to frequent the island. The Portuguese and Spanish soon gave up regularly calling at the island, partly because they used ports along the West African coast, but also because of attacks on their shipping, the desecration of their chapel and religious icons, destruction of their livestock and destruction of plantations by Dutch and English sailors.

Who probably located the island on their final leg of their circumnavigation trip?
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A: Englishman Sir Francis Drake

Problem: The National Art Gallery in Yerevan has more than 16,000 works that date back to the Middle Ages, which indicate Armenia's rich tales and stories of the times. It houses paintings by many European masters as well. The Modern Art Museum, the Children's Picture Gallery, and the Martiros Saryan Museum are only a few of the other noteworthy collections of fine art on display in Yerevan. Moreover, many private galleries are in operation, with many more opening every year, featuring rotating exhibitions and sales.
What is the earliest period the National Art Gallery has pieces from?
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Answer: the Middle Ages

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
With French, Belgian and Portuguese activity in the lower Congo River region undermining orderly incursion of tropical Africa, the Berlin Conference of 188485 was held to regulate the competition between the European powers in what was called the "Scramble for Africa" by defining "effective occupation" as the criterion for international recognition of territorial claims. The scramble continued into the 1890s, and caused Britain to reconsider its decision in 1885 to withdraw from Sudan. A joint force of British and Egyptian troops defeated the Mahdist Army in 1896, and rebuffed a French attempted invasion at Fashoda in 1898. Sudan was nominally made an Anglo-Egyptian Condominium, but a British colony in reality.
When did Britain withdraw from Sudan?
A: 1885

Context and question: On 3 December, Chopin complained about his bad health and the incompetence of the doctors in Majorca: "Three doctors have visited me ... The first said I was dead; the second said I was dying; and the third said I was about to die." He also had problems having his Pleyel piano sent to him. It finally arrived from Paris in December. Chopin wrote to Pleyel in January 1839: "I am sending you my Preludes [(Op. 28)]. I finished them on your little piano, which arrived in the best possible condition in spite of the sea, the bad weather and the Palma customs." Chopin was also able to undertake work on his Ballade No. 2, Op. 38; two Polonaises, Op. 40; and the Scherzo No. 3, Op. 39.
What did Frederic have trouble playing as a result of his growing illness?
Answer: piano

Question: Provided some additional requirements are met (e.g. providing an authoritative statement of the archivist), the United States patent office and the European Patent Office will accept date stamps from the Internet Archive as evidence of when a given Web page was accessible to the public. These dates are used to determine if a Web page is available as prior art for instance in examining a patent application.
Is there an answer to this question: What are used to determine if a patent is available?

Answer: unanswerable

Question: The polyphony of Christian a cappella music began to develop in Europe around the late 15th century, with compositions by Josquin des Prez. The early a cappella polyphonies may have had an accompanying instrument, although this instrument would merely double the singers' parts and was not independent. By the 16th century, a cappella polyphony had further developed, but gradually, the cantata began to take the place of a cappella forms. 16th century a cappella polyphony, nonetheless, continued to influence church composers throughout this period and to the present day. Recent evidence has shown that some of the early pieces by Palestrina, such as what was written for the Sistine Chapel was intended to be accompanied by an organ "doubling" some or all of the voices. Such is seen in the life of Palestrina becoming a major influence on Bach, most notably in the aforementioned Mass in B Minor. Other composers that utilized the a cappella style, if only for the occasional piece, were Claudio Monteverdi and his masterpiece, Lagrime d'amante al sepolcro dell'amata (A lover's tears at his beloved's grave), which was composed in 1610, and Andrea Gabrieli when upon his death it was discovered many choral pieces, one of which was in the unaccompanied style. Learning from the preceding two composeres, Heinrich Schutz utilized the a cappella style in numerous pieces, chief among these were the pieces in the oratorio style, which were traditionally performed during the Easter week and dealt with the religious subject matter of that week, such as Christ's suffering and the Passion. Five of Schutz's Historien were Easter pieces, and of these the latter three, which dealt with the passion from three different viewpoints, those of Matthew, Luke and John, were all done a cappella style. This was a near requirement for this type of piece, and the parts of the crowd were sung while the solo parts which were the quoted parts from either Christ or the authors were performed in a plainchant.
Is there an answer to this question: What piece was heavily influenced by Bach's Mass in B MInor?

Answer:
unanswerable