Problem: Military history of the United States:

The British, for their part, lacked both a unified command and a clear strategy for winning. With the use of the Royal Navy, the British were able to capture coastal cities, but control of the countryside eluded them. A British sortie from Canada in 1777 ended with the disastrous surrender of a British army at Saratoga. With the coming in 1777 of General von Steuben, the training and discipline along Prussian lines began, and the Continental Army began to evolve into a modern force. France and Spain then entered the war against Great Britain as Allies of the US, ending its naval advantage and escalating the conflict into a world war. The Netherlands later joined France, and the British were outnumbered on land and sea in a world war, as they had no major allies apart from Indian tribes.

 What two African countries entered the Revolutionary War against Britain?
---
A: unanswerable


Problem: The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage.
What is the defined boundary between visible and infrared light?
---
Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Architects such as Frank Lloyd Wright developed Organic architecture, in which the form was defined by its environment and purpose, with an aim to promote harmony between human habitation and the natural world with prime examples being Robie House and Fallingwater.
Who was instrumental in creating Organic architecture?
A: Frank Lloyd Wright


Context and question: Cuisine aroused a cultural pride in the accumulated richness of a long and varied past. The gentleman gourmet, such as Yuan Mei, applied aesthetic standards to the art of cooking, eating, and appreciation of tea at a time when New World crops and products entered everyday life. The Suiyuan Shidan written by him, detailed the culinary esthetics and theory, along with a wide range of recipes from the ruling period of Qianlong during Qing Dynasty. The Manchu Han Imperial Feast originated at the court. Although this banquet was probably never common, it reflected an appreciation by Han Chinese for Manchu culinary customs. Nevertheless, culinary traditionalists such as Yuan Mei lambasted the opulent culinary rituals of the Manchu Han Imperial Feast, saying that it is cause in part by "...the vulgar habits of bad chefs" and that "Display this trite are useful only for welcoming new relations through one’s gates or when the boss comes to visit." (皆惡廚陋習。只可用之於新親上門，上司入境)
What was the Manchu Han Imperial Feast?
Answer: appreciation by Han Chinese for Manchu culinary customs


Question: On 12 March 1999, the Czech Republic, Hungary, and Poland joined NATO; Bulgaria, Estonia, Latvia, Lithuania, Romania, and Slovakia joined in March 2004; Albania joined on 1 April 2009.
Is there an answer to this question: Hungary joined which organization in March 2004?

Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
New York City traces its roots to its 1624 founding as a trading post by colonists of the Dutch Republic and was named New Amsterdam in 1626. The city and its surroundings came under English control in 1664. New York served as the capital of the United States from 1785 until 1790. It has been the country's largest city since 1790. The Statue of Liberty greeted millions of immigrants as they came to the Americas by ship in the late 19th and early 20th centuries and is a globally recognized symbol of the United States and its democracy.
When was New York City established?
A:
1624