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In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.
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Article: If you're training for a marathon, a proper plan for water intake is important. Of course, there's the risk of dehydration . But athletes now know they can also get into trouble by drinking too much. Too much water intake can lower levels of sodium in the blood. The death of a 28-year-old woman following the Boston Marathon caught the attention of many runners and led to new research. Experts advise long distance runners to replace the liquids they sweat out. Their goal is to try to keep someone from not getting dehydrated by more than 2 percent of their body weight. One technique for deciding how much water you need is to get the exact numbers. Runners have to weigh themselves before and after a run to determine how much water they've lost. If their weight drops by more than 2 percent, they have not drunk enough water. Hyponatremia occurs when runners drink so much water that blood salt levels drop off. A study published last year tested 488 runners who completed the Boston Marathon and found 13 percent of them had dangerously low blood salt levels. The first sign that runners may notice is slightly swelling in the hands. They can't get their rings off, and then they might feel sick. They may not remember where they are. In fact, most runners get enough salt to get back to normal levels by eating just one meal after a run. Contrary to the old advice that runners should drink as much as they can to prevent dehydration, the new research has shown that the body is a remarkable machine that actually tells you via thirst when you need water.
Answer: a 28-year-old woman who died after a Boston Marathon
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The author of this passage is primarily concerned with _ .

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Article: "My dream has come true.I have always wanted to be a Grand Slam champion." These are the words of the Chinese tennis player Li Na after she became the first Asian woman to win the Australian Open final on Jan.25th.2014. "People were saying I'm getting old.So this is a great success for such an old woman." the 32-year-old girl joked. Miss Li has a tattoo . She has dyed her hair many different color1s.And, at the 2008 Beijing Olympics, she told her fans to "shut up" when they got too noisy in their support. Li Na was born in Wuhan.She started to play tennis at the age of 6.She once recalled: "As a child. I suffered a lot because every day I had to wake up early to practice.After school I had to practice more.I didn't have time to play." Luckily, the strong girl didn't give up. thus making history for Chinese tennis time after time.Now the new champion is already thinking about winning another Grand Slam title."When you have one title, surely you will think about another," she says. not hiding her ambition. "Chinese people are so lacking in confidence on the tennis court.If there is a person like me who can prove we Chinese can do it, the other young players in China will feel the same." she said.
Answer: 1988
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Li Na began to learn playing tennis in the year of _ .

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Article: Today, roller skating is easy and fun. But a long time ago, it wasn't easy at all. Before 1750, the idea of skating didn't exist. That changed because of a man named Joseph Merlin. Merlin's work was making musical instruments. In his spare time he liked to play the violin. Joseph Merlin was a man of ideas and dreams. People called him a dreamer. One day Merlin received an invitation to attend a fancy dress ball . He was very pleased and a little excited. As the day of the party came near, Merlin began to think how to make a grand entrance at the party. He thought he would get a lot of attention if he could skate into the room. Merlin tried different ways to make himself roll. Finally, he decided to put two wheels under each shoe. These were the first roller skates. Merlin was very proud of his invention and dreamed of arriving at the party on wheels while playing the violin. On the night of the party Merlin rolled into the room playing his violin. Everyone was astonished to see him. There was just one problem. Merlin had no way to stop his roller skates. He rolled on and on. Suddenly, he ran into a huge mirror that was hanging on the wall. Down fell the mirror, breaking to pieces. Nobody forget Merlin's grand entrance for a long time!
Answer: how people enjoyed themselves in the 18th century
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The text is mainly about _ .