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.
Example: Article: Homework can put you in a badmood , and that might actually be a good thing. Researchers from the University of Plymouth in England doubted whether mood might affect the way kids learn. To find out the answer, they did two experiments with children. The first experiment tested 30 kids. Someshapes were hidden inside a different, larger picture. The kids had to find the small shapes while sitting in a room with either cheerful or sad music playing in the background. To test their mood, the scientists asked the kids to point to one of five faces, from happy to sad. Children who listened to cheerful music tended to point to the smiley faces while the others pointed to the unhappy ones. The researchers found that sad kids took at least a second less to find the small shapes. They also found an average of three or four more shapes. In the second experiment, 61 children watched one of two scenes from a film. One scene was happy, and the other was sad. Just like in the first experiment, kids who saw the sad scene acted better compared to the others. The researchers guessed that feeling down makes people more likely to focus on a problem or difficult situation. Not all scientists agree with them, however. Other studies argued that maybe, that cheerful music in the first experiment distracted kids from finding shapes. While scientists work on finding out the answers, it still might be wise to choose when to do your tasks according to your mood. After eating a delicious ice cream, for example, write an essay. 
 Answer: whether mood affects their learning ability
Example solution: Researchers did experiments on kids in order to find out _ .
Example explanation: It is clearly mentioned in the article that to the check effect of mood on children is the main purpose of the experiment.

Problem: Article: A new study suggests that sad music might actually arouse positive emotions. The finding helps to explain why people enjoy listening to sad music, say Ai Kawakami and her colleagues from Tokyo University of the Arts and the RIKEN Brain Science Institute, Japan. Ai Kawakami and her colleagues asked 44 volunteers, including both musicians and nonspecialists, to listen to two pieces of sad music and one piece of happy music. Each participant was required to use a set of keywords to rate both their perception  of the music and their own emotional state. The sad pieces of music included Glinka's La Separation in F minor and Blumenfeld's Etude Sur Mer in G minor. The happy music piece was Granados's Allegro de Concierto in G major. To control the "happy" effect of major key, they also played the minor key  pieces in major key, and vise versa. The researchers explained that sad music aroused contradictory emotions because the participants of the study tended to feel sad to be more tragic and less romantic than they felt themselves while listening to it. " In general, sad music causes sadness in listeners, and sadness is regarded as an unpleasant emotion. If sad music actually arouses only unpleasant emotion, we would not listen to it," the researchers wrote in the study. "Music that is believed as sad actually causes romantic emotion as well as sad emotion.And people, regardless of their musical training, experience this ambivalent  emotion to listen to the sad music," added the researchers. Also, unlike sadness in daily life, sadness experienced through art actually feels pleasant, possibly because the latter does not cause an actual threat to our safety. This could help people to deal with their negative emotions in daily life, concluded the authors. "Emotion experienced by music has no direct danger or harm unlike the emotion experienced in everyday life. Therefore, we can even enjoy unpleasant emotion such as sadness. If we suffer from unpleasant emotion aroused through daily life, sad music might be helpful to negative emotion," they added. 
 Answer: sad music may help arouse positive emotions

Solution: People enjoy listening to sad music because    _   .