instruction:
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: Oxygen was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774, but Priestley is often given priority because his work was published first. The name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. Its name derives from the Greek roots oxys, "acid", literally "sharp", referring to the sour taste of acids and - -genes, "producer", literally "begetter", because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition. Common uses of oxygen includes the production cycle of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, in oxygen therapy and life support systems in aircraft, submarines, spaceflight and diving.
answer:
When did Carl Priestly discover oxygen?

question:
Passage: Like aluminium, copper is 100% recyclable without any loss of quality, regardless of whether it is in a raw state or contained in a manufactured product. In volume, copper is the third most recycled metal after iron and aluminium. It is estimated that 80% of the copper ever mined is still in use today. According to the International Resource Panel's Metal Stocks in Society report, the global per capita stock of copper in use in society is 3555 kg. Much of this is in more-developed countries (140300 kg per capita) rather than less-developed countries (3040 kg per capita).
answer:
What percent of copper is indestructible?

question:
Passage: The main crops grown are barley, wheat, buckwheat, rye, potatoes, and assorted fruits and vegetables. Tibet is ranked the lowest among China's 31 provinces on the Human Development Index according to UN Development Programme data. In recent years, due to increased interest in Tibetan Buddhism, tourism has become an increasingly important sector, and is actively promoted by the authorities. Tourism brings in the most income from the sale of handicrafts. These include Tibetan hats, jewelry (silver and gold), wooden items, clothing, quilts, fabrics, Tibetan rugs and carpets. The Central People's Government exempts Tibet from all taxation and provides 90% of Tibet's government expenditures. However most of this investment goes to pay migrant workers who do not settle in Tibet and send much of their income home to other provinces.
answer:
What are the main crops grown in China?