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.  

Sentence: Legislative powers are exercised by a 300-member elective unicameral Parliament. Statutes passed by the Parliament are promulgated by the President of the Republic. Parliamentary elections are held every four years, but the President of the Republic is obliged to dissolve the Parliament earlier on the proposal of the Cabinet, in view of dealing with a national issue of exceptional importance. The President is also obliged to dissolve the Parliament earlier, if the opposition manages to pass a motion of no confidence. 
Question: How often are elections help for parliament?
every four years

Sentence: Boston has a strong mayor – council government system in which the mayor (elected every fourth year) has extensive executive power. Marty Walsh became Mayor in January 2014, his predecessor Thomas Menino's twenty-year tenure having been the longest in the city's history. The Boston City Council is elected every two years; there are nine district seats, and four citywide "at-large" seats. The School Committee, which oversees the Boston Public Schools, is appointed by the mayor. 
Question: How often are elections for mayor held in Boston?
every fourth year

Sentence: Specialized comics periodicals formats vary greatly in different cultures. Comic books, primarily an American format, are thin periodicals usually published in colour. European and Japanese comics are frequently serialized in magazines—monthly or weekly in Europe, and usually black-and-white and weekly in Japan. Japanese comics magazine typically run to hundreds of pages. 
Question: How often are European serialized comics in magazines?

monthly or weekly

