Detailed Instructions: 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.
Problem:Passage: Until the 20th century, the language's spoken form was the language of only the upper noble classes and urban population, as Russian peasants from the countryside continued to speak in their own dialects. By the mid-20th century, such dialects were forced out with the introduction of the compulsory education system that was established by the Soviet government. Despite the formalization of Standard Russian, some nonstandard dialectal features (such as fricative [] in Southern Russian dialects) are still observed in colloquial speech.
Solution:
When did the Soviet government begin only speaking fricative?