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: In 1901, H.G. Wells, an English writer, wrote a book describing a trip to the moon. When the explorers landed on the moon, they discovered that the moon was full of underground cities. They expressed their surprise to the "moon people" they met. In turn, the "moon people" expressed their surprise. "Why," they asked, "are you traveling to outer space when you don't even use your inner space?" H.G. Wells could only imagine travel to the moon. In 1969, human beings really did land on the moon. People today know that there are no underground cities on the moon. However, the question that the "moon people" asked is still an interesting one. A growing number of scientists are seriously thinking about it. Underground systems are already in place. Many cities have underground car parks. In some cities, such as Tokyo, Seoul and Montreal, there are large underground shopping areas. The "Chunnel", a tunnel connecting England and France, is now complete. But what about underground cities? Japan's Taisei Corporation is designing a network of underground systems, called "Alice Cities." The designers imagine using surface space for public parks and using underground space for flats, offices, shopping, and so on. A solar dome would cover the whole city. Supporters of underground development say that building down rather than building up is a good way to use the earth's space. The surface, they say, can be used for farms, parks, gardens, and wilderness. H.G. Wells' "moon people" would agree. Would you?
Answer: lived in so many underground cities
The explorers in H. G. Wells' story were surprised to find that the "moon people" _ .

Article: Narayanan Krishnan was a bright, young, award-winning chef with a five-star hotel group in Switzerland. But a quick family visit home before heading for Europe changed everything. He saw a very old man under a bridge eating his own human waste for food while visiting a friend in the south Indian city of Madurai in 502. Shocked by this, Krishnan gave up his job within the week and returned home for good, convinced of his new cause. "That inspiration is a driving force still inside me as a flame--to serve all the mentally ill and the people who cannot take care of themselves," Krishnan said. He founded the organization Akshaya Trust in 503. In Hindu mythology , Goddess Annapoorani's "Akshaya bowl" fed the hungry endlessly, never using up its resources. Now 14, he has served more than 1.2 million meals--breakfast, lunch and dinner to India's homeless and the poor. Krishnan's day begins at 4 a.m. He and his team cover nearly 110 miles, routinely working in temperatures topping 100 degrees Fahrenheit. The hot meals he delivers are simple, tasty vegetarian food he personally prepares, packs and often hand-feeds to nearly 400 people each day. Krishnan carries the barber's tools and is trained in eight haircut styles that, along with a fresh shave, provide extra dignity to those he serves. He says many of the homeless seldom know their names or birthplaces, and none has the ability to beg, ask for help or offer thanks. They may be unfriendly or ill-willed because of their conditions, but Krishnan says this only makes him offer help more willingly.
Answer: knew the condition of the mentally ill
During his visit home, Krishnan _ .

Article: Our listener question this week comes from Abdullahi Farah, who wants to know about the life and work of Doctor Benjamin Carson. Doctor Carson is an internationally recognized doctor at Johns Hopkins Hospital in Baltimore, Maryland. He has been the director of Pediatric Neurosurgery at the hospital for twenty-five years. At the age of thirty-three, he became one of the youngest doctors in the United States to hold that position. And he was the first African-American to have that position at Johns Hopkins Hospital. Ben Carson is known for his work as a brain surgeon for children. For example, in nineteen eighty-seven, he led a team of seventy doctors and nurses in an operation to separate two babies joined at the head. Earlier attempts by other on other babies had failed. Doctor Carson successfully performed the operation. Both babies were able to survive independently. Doctor Carson has written four books. His first book, "Gifted Hands," tells the story of his life. Benjamin Carson was born in nineteen fifty-one in Detroit, Michigan. As a boy, Ben was not a good student. In fact, he was the worst in his class. When his mother learned of his failing grades she asked her sons to read two library books every week. She limited the amount of time they watched television. And she told them to respect every person. Ben Carson soon became the top student in his class. He went on to study at Yale University, one of the best universities in the country, and later to medical school at the University of Michigan. Doctor Carson has received many awards and honors. Last year he received the nation's highest civilian honor. Former President George W. Bush presented Benjamin Carson with the Presidential Medal of Freedom at a ceremony at the White House.
Answer: a radio
The passage is probably taken from _ .