You are given a background paragraph that describes one or more causal or qualitative relationships such as a relationship in economics or a scientific law and a story that makes use of the concepts or the relationship described in the provided paragraph. You need to come up with a question about the story that requires an understanding of the relationship described in the background paragraph. The generated question should not be answerable without both the background and story. Write a question about the story that requires a relationship in the background paragraph to answer. Check whether your question requires both the background paragraph and the story to answer. If your question can be answered by only one of these, try to rewrite your question so that it requires both. Note that "flipping" a word in the question can give rise to a new question where the answer will be different from the original question. Often, "flipping" a word gives rise to flipping the direction of the relationship, for example, from "increase" to "decrease."

Input: Consider Input: Background Paragraph: The water level is seasonal, being lowered by about 10 feet (3.0 m) over the winter. The reservoir fills in the spring from snow melt and underground springs. The lake is usually at full level by late spring, but in the occasional years of low snow melt and low rainfall, it may remain up to several feet below its typical level. Water is let out of the lake in the fall so that ice will not damage docks and other structures around the lake. This also leads to excellent water quality, as a significant portion of the water is replaced every year. 
Story: There are two hydroelectric dams in North Dakota. Both of them has large lakes or reservoirs, reservoir A and reservoir B. Since North Dakota has one the lowest unemployment rates in the country, it's hard to find an engineer to regulate and maintain the reservoirs. This year reservoir A could hire an engineer, but reservoir B failed to find an engineer. As a result, there is no one to regulate reservoir B. The engineer for reservoir A let the water out in the fall. But there was no one to do that for reservoir B.

Output: In which reservoir a good portion of the water would most likely be replaced?


Input: Consider Input: Background Paragraph: East Antarctica is colder than its western counterpart because of its higher elevation. Weather fronts rarely penetrate far into the continent, leaving the centre cold and dry. Despite the lack of precipitation over the central portion of the continent, ice there lasts for extended periods. Heavy snowfalls are common on the coastal portion of the continent, where snowfalls of up to 1.22 metres (48 in) in 48 hours have been recorded. 
Story: UK and France had scientific bases in Antarctica. UK had a base and studied the climate in East Antarctica, while France observed the climate in West Antarctica.

Output: Which country didn't observe ice lasting for extended periods?


Input: Consider Input: Background Paragraph: A comet tail—and coma—are features visible in comets when they are illuminated by the Sun and may become visible from Earth when a comet passes through the inner Solar System. As a comet approaches the inner Solar System, solar radiation causes the volatile materials within the comet to vaporize and stream out of the nucleus, carrying dust away with them. Separate tails are formed of dust and gases, becoming visible through different phenomena; the dust reflects sunlight directly and the gases glow from ionisation. Most comets are too faint to be visible without the aid of a telescope, but a few each decade become bright enough to be visible to the naked eye. 
Story: Year 2022 would be an interesting year when three comets would get scientists' attention - Comet A, Comet B, and Comet C. Comet A and C are very faint, but Comet B is very bright. Comet A would enter the inner solar system on February 10, 2022 and leave the inner solar system on February 20, 2022. Comet B would enter the inner solar system on February 18, 2022 and leave the inner solar system on February 26, 2022. Comet C would never enter the inner solar system.


Output: On Which date Comet B's dust would start reflecting sunlight?