Input: Read this: Hydrogen is highly soluble in many rare earth and transition metals and is soluble in both nanocrystalline and amorphous metals. Hydrogen solubility in metals is influenced by local distortions or impurities in the crystal lattice. These properties may be useful when hydrogen is purified by passage through hot palladium disks, but the gas's high solubility is a metallurgical problem, contributing to the embrittlement of many metals, complicating the design of pipelines and storage tanks.
Question: When are these useful?

Output: when hydrogen is purified by passage through hot palladium disks

Input: Read this: The earliest evidence of human inhabitants of modern day Chihuahua was discovered in the area of Samalayuca and Rancho Colorado. Clovis points have been found in northeastern Chihuahua that have been dated from 12,000 BC to 7000 BC. It is thought that these inhabitants were hunter gatherers. Inhabitants of the state later developed farming with the domestication of corn. An archeological site in northern Chihuahua known as Cerro Juanaquena revealed squash cultivation, irrigation techniques, and ceramic artifacts dating to around 2000 BC.
Question: Which vegetable were they found to have been farming?

Output: corn

Input: Read this: Colin Humphreys and W. G. Waddington of Oxford University considered the possibility that a lunar, rather than solar, eclipse might have taken place. They concluded that such an eclipse would have been visible, for thirty minutes, from Jerusalem and suggested the gospel reference to a solar eclipse was the result of a scribe wrongly amending a text. Historian David Henige dismisses this explanation as 'indefensible' and astronomer Bradley Schaefer points out that the lunar eclipse would not have been visible during daylight hours.
Question: For how many minutes did David Henige belive the lunar eclipse would be visible?

Output: unanswerable

Input: Read this: Romanesque architecture in Germany, Poland, the Czech Lands and Austria is characterised by its massive and modular nature. This is expressed in the Gothic architecture of Central Europe in the huge size of the towers and spires, often projected, but not always completed. The west front generally follows the French formula, but the towers are very much taller and, if complete, are surmounted by enormous openwork spires that are a regional feature. Because of the size of the towers, the section of the facade between them may appear narrow and compressed. The eastern end follows the French form. The distinctive character of the interior of German Gothic cathedrals is their breadth and openness. This is the case even when, as at Cologne, they have been modelled upon a French cathedral. German cathedrals, like the French, tend not to have strongly projecting transepts. There are also many hall churches (Hallenkirchen) without clerestory windows.
Question: What are hall churches in German cathedrals no longer known as?

Output:
unanswerable