Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Example Input: Researchers from France and Italy discovered that Canadian parents are less strict with their children than mothers and fathers in France and Italy. "Our most important finding was the difference between Canadians and the others," said Professor Michel Claes,the lead author of the study."Canadians focus on independence and negotiation.On the other hand,Italians,for example,exercise more control.We found Canadians seem to focus on negotiation in case of a conflict." Claes said Canada,France and Italy were selected for the study because they share important cultural and social factors."We chose FrenchCanadians because they share the same language as France,and originally came from France and share certain values.Italy was included because it was considered to have similar,strong and important family values," he explained. The researchers examined the emotional ties between parents and their children by questioning 1,256 students aged 11 to 19 years old. Canadian students reported less control and more free actions,according to the study.Italian parents were stricter and French parents were somewhere in the middle. Claes explains that the differences lie in education in Canada,France and Italy. "North America has its own educational values,which promote individualization.Tolerance and comprehension are encouraged.Italy,on the other hand,promotes respect of authority,control,and the need for permission." he said. Children from all three countries described their mothers as warm and communicative.Italian and Canadian children had similar feelings about their fathers,and reported high levels of emotional ties.But French fathers were generally thought by their children to be more distant and cold. "We were surprised by this," Claes admitted."It seems as though the relationships between French mothers and their children were becoming closer over time,while fathers maintain a form of distance and coldness,which is more of a source of conflict in France than in the other countries."
Example Output: According to Michel Claes,what mainly leads to the differences in parentchildren relationships among Canada,France and Italy?

Example Input: So that people in developed nations maintain a good lifestyle and people in developing nations have the ability to improve their lifestyles, natural resources must be conserved and protected (Figure 1.1). People are researching ways to find renewable alternatives to non-renewable resources. Here is a checklist of ways to conserve resources: Buy less stuff (use items as long as you can, and ask yourself if you really need something new). Reduce excess packaging (drink tap water instead of water from plastic bottles). Recycle materials such as metal cans, old cell phones, and plastic bottles. Purchase products made from recycled materials. Reduce pollution so that resources are maintained. Prevent soil erosion. Plant new trees to replace those that are cut down. Drive cars less, take public transportation, bicycle, or walk. Conserve energy at home (turn out lights when they are not needed). Click image to the left or use the URL below. URL: Click image to the left or use the URL below. URL:
Example Output: which one of these can you not recycle

Example Input: Scientists in Mexico have just begun a new study of one of the world's biggest pyramids: the Pyramid of the Sun, north of Mexico City. They're putting lots of small, high-tech machines under the pyramid to try to unlock some of its secrets. For thousands of years, people have tried to uncover the secrets of the pyramids. The people who built the pyramids made lots of secret doors and rooms to stop robbers from finding the treasures inside. However, there always have been some smart thieves in history. Now, almost all of Egypt's pyramids have been robbed, including the Great Pyramid of Khufu, which is the largest pyramid in the world. It is the only one of the ancient wonders of the world that is still standing. In AD 820, an Arab king named Abdullah AL Manum got a group of workers to dig their way into the Great Pyramid and have a look. Inside the pyramid, they found three rooms --- the Queen's Chamber, the Grand Gallery and the King's Chamber. But to their surprise, the men didn't find the treasures they wanted. The Queen's and King's Chambers were both empty! Where were the King's mummy and his treasures? Had someone already taken them away? The huge stone doors at the pyramid's entrance were still closed when AL Manum's men went inside. How had the thieves got in and out? Since then, many people have gone inside the Great Pyramid to have a look or to try to take things. But still, no other chambers or walkways have been found. In 2002, an American team made the most recent visit to the Great Pyramid. Scientists sent a robot into the pyramid, but they only found a mysterious locked stone door.
Example Output:
What is the purpose of making some secret doors to the pyramids?