In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
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Question: What needs consistency?, Context: The simplest valve gears give events of fixed length during the engine cycle and often make the engine rotate in only one direction. Most however have a reversing mechanism which additionally can provide means for saving steam as speed and momentum are gained by gradually "shortening the cutoff" or rather, shortening the admission event; this in turn proportionately lengthens the expansion period. However, as one and the same valve usually controls both steam flows, a short cutoff at admission adversely affects the exhaust and compression periods which should ideally always be kept fairly constant; if the exhaust event is too brief, the totality of the exhaust steam cannot evacuate the cylinder, choking it and giving excessive compression ("kick back").[citation needed]

Answer: exhaust and compression periods


Question: In early August 2008, who was not working for the AFL, Ed Policy or David Baker?, Context: After 12 years as commissioner of the AFL, David Baker retired unexpectedly on July 25, 2008, just two days before ArenaBowl XXII; deputy commissioner Ed Policy was named interim commissioner until Baker's replacement was found. Baker explained, "When I took over as commissioner, I thought it would be for one year. It turned into 12. But now it's time."

Answer: David Baker


Question: Where have the figures represented been collected?, Context: The climate of Saint Helena is tropical, marine and mild, tempered by the Benguela Current and trade winds that blow almost continuously. The climate varies noticeably across the island. Temperatures in Jamestown, on the north leeward shore, range between 21–28 °C (70–82 °F) in the summer (January to April) and 17–24 °C (63–75 °F) during the remainder of the year. The temperatures in the central areas are, on average, 5–6 °C (9.0–10.8 °F) lower. Jamestown also has a very low annual rainfall, while 750–1,000 mm (30–39 in) falls per year on the higher ground and the south coast, where it is also noticeably cloudier. There are weather recording stations in the Longwood and Blue Hill districts.

Answer:
weather recording stations in the Longwood and Blue Hill districts