Provided the input sentence, you're expected to write 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. Don't create questions which have explicit mentions of answers in the text. Instead, it has to be implied from what is given. In other words, we want you to use "instinct" or "common sense". Also, the written questions are not required to have a single correct answer.
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Question: Sentence: He tried and tried to please every person who came to the store, but they all picked smaller puppies.

Answer: How often do people come to the store ?


Question: Sentence: The Persian Gulf War destroyed much of the country's medical infrastructure, according to a report by the World Health Organization.

Answer: How often did the Persian Gulf War take place?


Question: Sentence: At current rates of use, coal will last about 300 years.

Answer:
How often are the coal reserves calculated?


