Definition: 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.
Input: Passage: The language possesses five vowels (or six, under the St. Petersburg Phonological School), which are written with different letters depending on whether or not the preceding consonant is palatalized. The consonants typically come in plain vs. palatalized pairs, which are traditionally called hard and soft. (The hard consonants are often velarized, especially before front vowels, as in Irish). The standard language, based on the Moscow dialect, possesses heavy stress and moderate variation in pitch. Stressed vowels are somewhat lengthened, while unstressed vowels tend to be reduced to near-close vowels or an unclear schwa. (See also: vowel reduction in Russian.)
Output:
How many classes are there at the St. Petersburg Phonological School?