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 Input: 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
Example Output: The negative effect of planting trees in deserts is that _ .

Example Input: Article: Blue whales are the largest animals ever known to have existed on the planet, and they can grow to a length of 100 feet and weigh more than 330,000 pounds. But recently researchers have found that these whales are on the move and they have migrated (moved) from California waters to areas off Canada and Alaska for the first time since commercial whaling ended in 1965. The researchers identified 15 blue whales that have appeared off the coast of British Columbia and the Gulf of Alaska since 1997. Four of these whales were recognized as ones that were once sighted off California shores, suggesting that the whales are returning to an old migration pattern between the coasts. Before commercial whaling began in the early 1900s, blue whales were found widely throughout the North Pacific and California waters. But from the 1920s to the 1960s, whaling severely reduced the whale populations. Blue whales never recovered in the Northern Pacific, making sightings in this area rare. However, much larger groups of whales have been observed close to California since the 1970s. The scientists had previously thought that the California population was separate from the population that had historically lived in North Pacific waters. But the current study shows that whales off the coast of British Columbia and the Gulf of Alaska are likely part of the California population.[:] To identify the blue whales, the researchers looked at photos of _ taken in the North Pacific Ocean and compared them with a library of blue whale pictures taken along the West Coast of the United States and Southern Pacific. Up to now, the researchers are not quite sure why the whales are changing their migration patterns, but they suspect that the whales may be following their food moving farther north by the changes in ocean conditions.
Answer: moving from the south to the north
Example Output: According to the passage, blue whales are _ .

Example Input: Article: When I was a boy, my father told me that he could do anything he wanted to.Dad said that he wanted to be the first to develop color1 prints in our city, and so he did. When I was 16, Dad looked closely at the violin I played and announced that he wanted to make one. He read about violin making, and then became a violinmaker at the age of 43.He bought the tools and materials, opened a small store and set Mom up as the shopkeeper, while he worked at a local company. He retired from the company 17 years later and continued to make violins and other instruments. Dad often guessed why the Stradivarius violins sound so beautiful. Some experts claimed that it was the unique varnish that gave those instruments their beautiful sound. Dad argued that chemists could analyze the varnish--if that were the answer. One of Dad's friends asked him once which kind of wood was used to make violins.When Dad explained that the top was made of spruce , his friend said that he had an old piece of spruce Dad might be interested in. He worked for the next 12 months making a violin from the wood that his friend had given him. It proved to be a superior violin and it would become Dad's masterpiece. He was convinced that the secret of the Stradivarius sound was in the wood itself. Later, the instrument was stolen.Dad's spirit was broken by the robbery, and he stopped making instruments. But he kept the music shop until he was 80 years old, selling guitars and violins. My father has been gone for 14 years now. The violin has been missing for more than 25 years.Somewhere a musician is playing a late 20th century violin with an excellent tone. The owner today may never understand why this ordinary-looking violin sounds so much like a Stradivarius.
Answer: to prove that his father could do anything he wanted to
Example Output:
The author mentions his father's developing color1 prints _ .