Problem: A cappella:

In July 1943, as a result of the American Federation of Musicians boycott of US recording studios, the a cappella vocal group The Song Spinners had a best-seller with "Comin' In On A Wing And A Prayer". In the 1950s several recording groups, notably The Hi-Los and the Four Freshmen, introduced complex jazz harmonies to a cappella performances. The King's Singers are credited with promoting interest in small-group a cappella performances in the 1960s. In 1983 an a cappella group known as The Flying Pickets had a Christmas 'number one' in the UK with a cover of Yazoo's (known in the US as Yaz) "Only You". A cappella music attained renewed prominence from the late 1980s onward, spurred by the success of Top 40 recordings by artists such as The Manhattan Transfer, Bobby McFerrin, Huey Lewis and the News, All-4-One, The Nylons, Backstreet Boys and Boyz II Men.[citation needed]

When did the American Federation of Musicians introduce jazz to a cappella?
---
A: unanswerable

Problem: In November 1956, Eisenhower forced an end to the combined British, French and Israeli invasion of Egypt in response to the Suez Crisis, receiving praise from Egyptian president Gamal Abdel Nasser. Simultaneously he condemned the brutal Soviet invasion of Hungary in response to the Hungarian Revolution of 1956. He publicly disavowed his allies at the United Nations, and used financial and diplomatic pressure to make them withdraw from Egypt. Eisenhower explicitly defended his strong position against Britain and France in his memoirs, which were published in 1965.
What was the combined Israeli-British-French invasion in response to?
---
Answer: Suez Crisis

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
During the 16th and 17th centuries slave traders began to raid the region as part of the expansion of the Saharan and Nile River slave routes. Their captives were slaved and shipped to the Mediterranean coast, Europe, Arabia, the Western Hemisphere, or to the slave ports and factories along the West and North Africa or South the Ubanqui and Congo rivers. In the mid 19th century, the Bobangi people became major slave traders and sold their captives to the Americas using the Ubangi river to reach the coast. During the 18th century Bandia-Nzakara peoples established the Bangassou Kingdom along the Ubangi River.
What river saw the establishment of a new Kingdom?
A: Ubangi River

Context and question: In order to explain the common features shared by Sanskrit and other Indo-European languages, many scholars have proposed the Indo-Aryan migration theory, asserting that the original speakers of what became Sanskrit arrived in what is now India and Pakistan from the north-west some time during the early second millennium BCE. Evidence for such a theory includes the close relationship between the Indo-Iranian tongues and the Baltic and Slavic languages, vocabulary exchange with the non-Indo-European Uralic languages, and the nature of the attested Indo-European words for flora and fauna.
When is it thought that early speakers of Sanskrit came to India?
Answer: early second millennium BCE

Question: Following the American Revolutionary War, the United States faced potential military conflict on the high seas as well as on the western frontier. The United States was a minor military power during this time, having only a modest army, Marine corps, and navy. A traditional distrust of standing armies, combined with faith in the abilities of local militia, precluded the development of well-trained units and a professional officer corps. Jeffersonian leaders preferred a small army and navy, fearing that a large military establishment would involve the United States in excessive foreign wars, and potentially allow a domestic tyrant to seize power.
Is there an answer to this question: The founding fathers had faith in what military groups?

Answer: local militia

Question: The very large and ornate School Hall and School Library (by L K. Hall) were erected in 1906-8 across the road from Upper School as the school's memorial to the Etonians who had died in the Boer War. Many tablets in the cloisters and chapel commemorate the large number of dead Etonians of the Great War. A bomb destroyed part of Upper School in World War Two and blew out many windows in the Chapel. The college commissioned replacements by Evie Hone (194952) and by John Piper and Patrick Reyntiens (1959 onwards).
Is there an answer to this question: Who was one of the prominent Etonians who died in the Great War?

Answer:
unanswerable