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.

[Q]: Article: To prevent the deserts coming near, China has planted billions of trees---to replace destroyed forests and as barriers against the sand. This isn't a cure, though, say experts, as thirsty trees can make the problem worse by taking in groundwater. "Planting tress is one way, but it isn't that simple. It doesn't solve the basic issue of water resources," says Wu Bo, a professor. "We need to calculate how much water the trees will absorb, or else it could have a negative effect." Villagers in Zhengxin have taken on this challenge, with limited success. When the irrigation channels began to run dry, Lu Xianglin switched from wheat to cotton on his land. He also planted trees to protect his fields from sandstorms. He says he still gets good yields using flood irrigation and earns a good income for his family. Other farmers haven't stuck it out : about one in three have left Zhengxin in the past 10 years after their wheat crops died. Young people who can find jobs in the towns rarely return. Last week, Mr Lu joined the other men in his village on a government-arranged trip to see the land that has been set aside for their relocation, nearly 40 miles to the south. The next day, he was back, shaking his head at the plan. The idea of uprooting his family troubles him, as does the idea of giving up the land that fed his forefathers. He prefers to stay and keep up the fight. "With enough water, this problem can be solved," Lu says. "We can plant trees and grass, and they will grow bigger. That will stop the desert." Experts say that farmers could switch to drip irrigation to lessen their water intake for growing crops. Elsewhere in the region, farmers have built brick greenhouses as part of a plan to grow vegetables using less water. Roadside signs urge farmers to "Save Water, Protect the Environment".
Answer: it can make groundwater become less
[A]: The negative effect of planting trees in deserts is that _ .

[Q]: Article: Hong Kong businesses hit by nearly two months of illegal street occupations breathed a collective sigh of relief on Wednesday. Police finally cleared illegal protesters camped at the main intersection in the Mong Kok district, arresting two student leaders. More than 7,000 officers backed bailiffs (,)clearing occupied sections of Argyle Street and Nathan Road. The two-day operation saw 148 people arrested for various offenses, including contempt of court, resisting arrest, possession of offensive weapons, unlawful gathering and attacking police. The Chief Leader Stephen Hui said 22 officers were injured during the clearances. Police used pepper spray and batons to keep protesters from reclaiming cleared roads and from spreading the illegal occupation to neighboring streets. Six-lane Nathan Road, which goes through the heart of Kowloon, was cleared after nearly five hours. However, comments on the Internet said protesters were looking to reoccupy roads later in the evening. This week's actions mark the first time the authorities have successfully cleared one of the three main protest sites, which sprang up after demonstrators seized key intersections in late September to press for unconstitutional reforms. Contractor Kwan Sui-sum, 55, said he wished the Nathan Road clearance had come earlier, as he has had to pay HK$20,000 ($2,580) after the protesters delayed building reconstruction work. The owner of the Chung Hing Duty Free drug store was cautiously optimistic and eager for his store at the corner of the cleared intersection to get back to business. Sales dropped by 40 percent during the occupation, he said. "I'm not worried about the guess that the protesters will return. I trust in Hong Kong's rule of law and in the police," the man said, who wished to remain unknown as he fears attack from protesters. But five stores at a cleared site owned by jewelry chain Chow Tai Fook were still closed hours later. A company spokesman said the outlets will remain shut while it continues to monitor the situation.
Answer: the Hong Kong police cleared the roads at a cost
[A]: You can infer from the passage that _ .

[Q]: Article: I have a friend named Monty Roberts who owns a horse ranch . He has let me use his house to put on fund-raising events. The last time I was there he introduced me by saying: "I want to tell you a story. It all goes back to a story about a young man who was the son of an itinerant horse trainer who would go from stable to stable, race track to race track, farm to farm and ranch to ranch, training horses. As a result, the boy's high school career was continually interrupted. When he was a senior, he was asked to write a paper about what he wanted to be and do when he grew up. "That night he wrote a seven-page paper describing his goal of someday owning a horse ranch. He wrote about his dream in great detail and he even drew a diagram of a 200-acre ranch, showing the location of all the buildings, the stables and the track. Then he drew a detailed floor plan for a 4,000-square-foot house that would sit on a 200-acre dream ranch. "He put a great deal of his heart into the project and the next day he handed it in to his teacher. Two days later he received his paper back. On the front page was a large red F with a note that read, 'See me after class.' "The boy with the dream went to see the teacher after class and asked, 'Why did I receive an F?' The teacher said, 'This is an unrealistic dream for a young boy like you. You have no money. You come from an itinerant family. You have no resources. Owning a horse ranch requires a lot of money. You have to buy the land. You have to pay for the original breeding stock and later you'll have to pay large stud fees. There's no way you could ever do it.' Then the teacher added, 'If you will rewrite this paper with a more realistic goal, I will reconsider your grade.' "The boy went home and thought about it long and hard. He asked his father what he should do. His father said, 'Look, son, you have to make up your own mind on this. However, I think it is a very important decision for you.' Finally, after a week, the boy turned in the same paper, making no changes at all. He stated, 'You can keep the F and I'll keep my dream.' " Monty then turned to the group present and said, "I tell you this story because you are sitting in my 4,000-square-foot house in the middle of my 200-acre horse ranch. I still have that school paper framed over the fireplace." He added, "The best part of the story is that two years ago that same schoolteacher brought 30 kids to camp out on my ranch for a week. When the teacher was leaving, he said, 'Look, Monty, I can tell you this now. When I was your teacher, I was something of a dream stealer. During those years I stole a lot of kids' dreams. Fortunately you had enough courage not to give up yours.' " "Don't let anyone steal your dreams. Follow your heart, no matter what," Monty at last concluded.
Answer: the teacher doubted his chance of success
[A]:
The teacher asked the boy to rewrite the paper because _ .