Problem: Anti-aircraft warfare:

However, the problem of deflection settings — 'aim-off' — required knowing the rate of change in the target's position. Both France and UK introduced tachymetric devices to track targets and produce vertical and horizontal deflection angles. The French Brocq system was electrical, the operator entered the target range and had displays at guns; it was used with their 75 mm. The British Wilson-Dalby gun director used a pair of trackers and mechanical tachymetry; the operator entered the fuse length, and deflection angles were read from the instruments.

What did the tachymetric devices do?
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A: track targets and produce vertical and horizontal deflection angles


Problem: From the middle of the 18th century, exploration and publication changed the course of British architecture towards a purer vision of the Ancient Greco-Roman ideal. James 'Athenian' Stuart's work The Antiquities of Athens and Other Monuments of Greece was very influential in this regard, as were Robert Wood's Palmyra and Baalbec. A combination of simple forms and high levels of enrichment was adopted by the majority of contemporary British architects and designers. The revolution begun by Stuart was soon to be eclipsed by the work of the Adam Brothers, James Wyatt, Sir William Chambers, George Dance, James Gandon and provincially based architects such as John Carr and Thomas Harrison of Chester.
What move towards a less pure form of Greco-Roman architecture during the eighteenth century?
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Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Predators are often another organism's prey, and likewise prey are often predators. Though blue jays prey on insects, they may in turn be prey for cats and snakes, and snakes may be the prey of hawks. One way of classifying predators is by trophic level. Organisms that feed on autotrophs, the producers of the trophic pyramid, are known as herbivores or primary consumers; those that feed on heterotrophs such as animals are known as secondary consumers. Secondary consumers are a type of carnivore, but there are also tertiary consumers eating these carnivores, quartary consumers eating them, and so forth. Because only a fraction of energy is passed on to the next level, this hierarchy of predation must end somewhere, and very seldom goes higher than five or six levels, and may go only as high as three trophic levels (for example, a lion that preys upon large herbivores such as wildebeest, which in turn eat grasses). A predator at the top of any food chain (that is, one that is preyed upon by no organism) is called an apex predator; examples include the orca, sperm whale, anaconda, Komodo dragon, tiger, lion, tiger shark, Nile crocodile, and most eagles and owls—and even omnivorous humans and grizzly bears. An apex predator in one environment may not retain this position as a top predator if introduced to another habitat, such as a dog among alligators, a skunk in the presence of the great horned owl immune to skunk spray, or a snapping turtle among jaguars; a predatory species introduced into an area where it faces no predators, such as a domestic cat or a dog in some insular environments, can become an apex predator by default.
What is the top predator in an environment called? 
A: apex predator


Context and question: Many popular museums, such as the San Diego Museum of Art, the San Diego Natural History Museum, the San Diego Museum of Man, the Museum of Photographic Arts, and the San Diego Air & Space Museum are located in Balboa Park, which is also the location of the San Diego Zoo. The Museum of Contemporary Art San Diego (MCASD) is located in La Jolla and has a branch located at the Santa Fe Depot downtown. The downtown branch consists of two building on two opposite streets. The Columbia district downtown is home to historic ship exhibits belonging to the San Diego Maritime Museum, headlined by the Star of India, as well as the unrelated San Diego Aircraft Carrier Museum featuring the USS Midway aircraft carrier.
Which museum houses the USA Midway aircraft carrier?
Answer: unanswerable


Question: In the mid-19th century, Serbian (led by self-taught writer and folklorist Vuk Stefanović Karadžić) and most Croatian writers and linguists (represented by the Illyrian movement and led by Ljudevit Gaj and Đuro Daničić), proposed the use of the most widespread dialect, Shtokavian, as the base for their common standard language. Karadžić standardised the Serbian Cyrillic alphabet, and Gaj and Daničić standardized the Croatian Latin alphabet, on the basis of vernacular speech phonemes and the principle of phonological spelling. In 1850 Serbian and Croatian writers and linguists signed the Vienna Literary Agreement, declaring their intention to create a unified standard. Thus a complex bi-variant language appeared, which the Serbs officially called "Serbo-Croatian" or "Serbian or Croatian" and the Croats "Croato-Serbian", or "Croatian or Serbian". Yet, in practice, the variants of the conceived common literary language served as different literary variants, chiefly differing in lexical inventory and stylistic devices. The common phrase describing this situation was that Serbo-Croatian or "Croatian or Serbian" was a single language. During the Austro-Hungarian occupation of Bosnia and Herzegovina, the language of all three nations was called "Bosnian" until the death of administrator von Kállay in 1907, at which point the name was changed to "Serbo-Croatian".
Is there an answer to this question: In 1850 what dialect did Serbian and Croatian writers propose to use as a standard language?

Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Compounds that contain a carbon-copper bond are known as organocopper compounds. They are very reactive towards oxygen to form copper(I) oxide and have many uses in chemistry. They are synthesized by treating copper(I) compounds with Grignard reagents, terminal alkynes or organolithium reagents; in particular, the last reaction described produces a Gilman reagent. These can undergo substitution with alkyl halides to form coupling products; as such, they are important in the field of organic synthesis. Copper(I) acetylide is highly shock-sensitive but is an intermediate in reactions such as the Cadiot-Chodkiewicz coupling and the Sonogashira coupling. Conjugate addition to enones and carbocupration of alkynes can also be achieved with organocopper compounds. Copper(I) forms a variety of weak complexes with alkenes and carbon monoxide, especially in the presence of amine ligands.
What is produced when copper compounds are treated with organolithium reagents?
A:
Gilman reagent