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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.

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
Solution: Researchers did experiments on kids in order to find out _ .
Why? It is clearly mentioned in the article that to the check effect of mood on children is the main purpose of the experiment.

New input: Article: The Baima is a minority group of about 1,400 people. They have lived in Northern Sichuan and Southern Gansu Provinces for centuries. They have long depended on the forests as their main source of income. But since a ban on cutting down forests was introduced in the late 1990s to fight yearly flooding, the villagers have had to look for other means of earning a living. Several are now in the process of developing a small tourism industry as their lands are rich in forests and natural scenery and are the home of the giant pandas. Xiangshujia, in particular, is becoming a popular bed and breakfast centre for tourists heading to Wanglang to see the giant pandas. Visitors are also starting to take notice of the Baima people themselves. As our jeep stopped in the courtyard of a house, we were greeted by the village leader Li Qin and young Baima girls dressed in traditional costumes with white feathers in their hair. As we took our places on wooden benches near an open fire, the girls began to sing traditional songs as they served us. "The number of tourists is growing," said Li Qin. "We realize that to attract visitors we have to show our culture by offering more traditional singing and dancing and ensuring our houses are built in the traditional way." Relations between the Baima people and the reserve were once tense following the ban on cutting down forests. Villagers had to make a new living. They entered the Wanglang Nature Reserve to collect wild mushrooms and herbs , often at the expense of disturbing the pandas' habitat. But things greatly improved as villagers started receiving training in how to sell things to tourists. "Our aim was to deter the villagers, because they often disturbed the pandas' habitat, and to ensure they could have a long-lasting means of earning a living," emphasized Chen Youping, director of the Wanglang Nature Reserve. "All the money from the reserve goes back into the community and conservation projects," said Chen. "We take into consideration first the animals and then tourism."
Answer: it was necessary before they sang traditional songs
Solution:
We can infer that the Baima girls wore their traditional costumes to greet visitors mainly because _ .