In this task, you're given passages that contain mentions of a time duration related quesry and we are supposed to write answer to a question that involves event “frequency", which refers to how often an event is likely to be repeated. For example, "taking showers" typically occurs ~5 times a week, "going to saturday market" usually happens every few weeks/months, etc. 
 Note that a lot of the questions could have more than one correct answers. We only need a single most-likely answer. Please try to keep your "answer" as simple as possible. Concise and simple "answer" is preferred over those complex and verbose ones.  

Q: Sentence: His family was long associated with the teaching of elocution: his grandfather, Alexander Bell, in London, his uncle in Dublin, and his father, in Edinburgh, were all elocutionists. His father published a variety of works on the subject, several of which are still well known, especially his The Standard Elocutionist (1860), which appeared in Edinburgh in 1868. The Standard Elocutionist appeared in 168 British editions and sold over a quarter of a million copies in the United States alone. In this treatise, his father explains his methods of how to instruct deaf-mutes (as they were then known) to articulate words and read other people's lip movements to decipher meaning. Bell's father taught him and his brothers not only to write Visible Speech but to identify any symbol and its accompanying sound. Bell became so proficient that he became a part of his father's public demonstrations and astounded audiences with his abilities. He could decipher Visible Speech representing virtually every language, including Latin, Scottish Gaelic, and even Sanskrit, accurately reciting written tracts without any prior knowledge of their pronunciation. 
Question: The Standard Elocutionist was printed how many times?

A: 168
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Q: Sentence: Birds need to alter their metabolism in order to meet the demands of migration. The storage of energy through the accumulation of fat and the control of sleep in nocturnal migrants require special physiological adaptations. In addition, the feathers of a bird suffer from wear-and-tear and require to be molted. The timing of this molt - usually once a year but sometimes twice - varies with some species molting prior to moving to their winter grounds and others molting prior to returning to their breeding grounds. Apart from physiological adaptations, migration sometimes requires behavioural changes such as flying in flocks to reduce the energy used in migration or the risk of predation. 
Question: How often do birds molt?

A: usually once a year
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Q: Sentence: Numerous recordings of Chopin's works are available. On the occasion of the composer's bicentenary, the critics of The New York Times recommended performances by the following contemporary pianists (among many others): Martha Argerich, Vladimir Ashkenazy, Emanuel Ax, Evgeny Kissin, Murray Perahia, Maurizio Pollini and Krystian Zimerman. The Warsaw Chopin Society organizes the Grand prix du disque de F. Chopin for notable Chopin recordings, held every five years. 
Question: How often is the Grand prix du disque de F. Chopin for notable Chopin recordings held?

A:
every five years.
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