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: The Melbourne rail network has its origins in privately built lines from the 1850s gold rush era, and today the suburban network consists of 209 suburban stations on 16 lines which radiate from the City Loop, a partially underground metro section of the network beneath the Central Business District (Hoddle Grid). Flinders Street Station is Melbourne's busiest railway station, and was the world's busiest passenger station in 1926. It remains a prominent Melbourne landmark and meeting place. The city has rail connections with regional Victorian cities, as well as direct interstate rail services to Sydney and Adelaide and beyond which depart from Melbourne's other major rail terminus, Southern Cross Station in Spencer Street. In the 2013–2014 financial year, the Melbourne rail network recorded 232.0 million passenger trips, the highest in its history. Many rail lines, along with dedicated lines and rail yards are also used for freight. The Overland to Adelaide departs Southern Cross twice a week, while the XPT to Sydney departs twice a day. 
Question: How often does the XPT to Sydney depart?
[A]: twice a day


[Q]: Sentence: Mechanical pulping yields almost a tonne of pulp per tonne of dry wood used, which is why mechanical pulps are sometimes referred to as "high yield" pulps. With almost twice the yield as chemical pulping, mechanical pulps is often cheaper. Mass-market paperback books and newspapers tend to use mechanical papers. Book publishers tend to use acid-free paper, made from fully bleached chemical pulps for hardback and trade paperback books. 
Question: How many times more yield does the mechanical pulping process produce when compared to to the chemical pulping process?
[A]: twice


[Q]: Sentence: The Special Clerical Court handles crimes allegedly committed by clerics, although it has also taken on cases involving lay people. The Special Clerical Court functions independently of the regular judicial framework and is accountable only to the Supreme Leader. The Court's rulings are final and cannot be appealed. The Assembly of Experts, which meets for one week annually, comprises 86 "virtuous and learned" clerics elected by adult suffrage for eight-year terms. As with the presidential and parliamentary elections, the Guardian Council determines candidates' eligibility. The Assembly elects the Supreme Leader and has the constitutional authority to remove the Supreme Leader from power at any time. It has not challenged any of the Supreme Leader's decisions. 
Question: How often does the Assembly of Experts meet?
[A]:
one week annually