This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
--------
Question: Passage: A few glaciers have periods of very rapid advancement called surges. These glaciers exhibit normal movement until suddenly they accelerate, then return to their previous state. During these surges, the glacier may reach velocities far greater than normal speed. These surges may be caused by failure of the underlying bedrock, the pooling of meltwater at the base of the glacier — perhaps delivered from a supraglacial lake — or the simple accumulation of mass beyond a critical "tipping point". Temporary rates up to 90 m (300 ft) per day have occurred when increased temperature or overlying pressure caused bottom ice to melt and water to accumulate beneath a glacier.

Answer: What is the term for a gradual increase in a glaciers speed?


Question: Passage: Cork is home to the RTÉ Vanbrugh Quartet, and to many musical acts, including John Spillane, The Frank And Walters, Sultans of Ping, Simple Kid, Microdisney, Fred, Mick Flannery and the late Rory Gallagher. Singer songwriter Cathal Coughlan and Sean O'Hagan of The High Llamas also hail from Cork. The opera singers Cara O'Sullivan, Mary Hegarty, Brendan Collins, and Sam McElroy are also Cork born. Ranging in capacity from 50 to 1,000, the main music venues in the city are the Cork Opera House (capacity c.1000), Cyprus Avenue, Triskel Christchurch, the Roundy, the Savoy and Coughlan's.[citation needed] Cork's underground scene is supported by Plugd Records.[citation needed]

Answer: What Opera singers currently lives in Cork?


Question: Passage: The first known smelting of iron began in Anatolia, around 1800 BC. Called the bloomery process, it produced very soft but ductile wrought iron. By 800 BC, iron-making technology had spread to Europe, arriving in Japan around 700 AD. Pig iron, a very hard but brittle alloy of iron and carbon, was being produced in China as early as 1200 BC, but did not arrive in Europe until the Middle Ages. Pig iron has a lower melting point than iron, and was used for making cast-iron. However, these metals found little practical use until the introduction of crucible steel around 300 BC. These steels were of poor quality, and the introduction of pattern welding, around the 1st century AD, sought to balance the extreme properties of the alloys by laminating them, to create a tougher metal. Around 700 AD, the Japanese began folding bloomery-steel and cast-iron in alternating layers to increase the strength of their swords, using clay fluxes to remove slag and impurities. This method of Japanese swordsmithing produced one of the purest steel-alloys of the early Middle Ages.

Answer:
Where was bronze first smelted