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.
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Question: Article: The place is England. The year is 1928. One of the founding theorists of quantum mechanics , Paul Dirac, is scratching his head because solutions to his equations have _ unexpected results. For the solutions to make sense, he reasons, there must be a particle that has the mass of an electron but the opposite charge. At the time, such a thing was not known to exist. Several years pass before American physicist Carl Anderson observes a "positive" electron, or positron that confirms Dirac's prediction. Antimatter , as the name implies, can be described as the opposite of ordinary matter. Every particle in the universe has characteristics such as mass and charge. With antimatter, the mass remains constant, but the sign of the charge is reversed. All particles have an antimatter counterpart , even the chargeless neutron . Unlike matter, antimatter is not common. Unless you're in the upper atmosphere, or inside a particle accelerator, you're not going to come across it. "Antimatter was not always so rare," Stephane Coutu, Penn State particle physicist says. There was a time when it was as prevalent as matter itself. "Right after the Big Bang ," Coutu explains, "we believe there must have been exactly the same amounts of matter and antimatter...and yet owing to some small asymmetry in the laws of particle interactions, all of the antimatter and most of the matter in the early universe was annihilated . We are left today with the resulting matter-dominated universe." Science fiction is rife with tales of high-energy particle annihilation, and indeed, antimatter weapons have appeared in current bestselling novels. This is unrealistic, Coutu says. "[It] would be very impractical owing to very great difficulties in producing and maintaining significant amounts of antimatter." Technology that uses the properties of antimatter is actually feasible outside of science fiction, however. Positron emission tomography (PET) is a medical technique that can be used to detect cancer, measure blood flow and detect coronary artery disease. While antimatter may never be used as a bomb, it certainly has a positive future in life-saving medical diagnostic tools, the anti-weapon.
Answer: It's not easy to produce and maintain large quantities of antimatter

Answer: According to Coutu, _ .

Question: Article: Our first winter in Canada was the happiest we have experienced. We were living in the countryside then and had just arrived from Hong Kong that autumn. One evening in mid December snow began to fall. When we looked out of the window and saw that it was snowing, we all cheered. It was the first snow we had ever seen and we were excited. We could hardly wait for the snow to stop so that we could go out to play. Next morning when we woke up, it was still snowing. We switched on the radio and learned that more than ten inches of snow had falled during the night and that since the roads were blocked there would be no school that day. We jumped up and down for joy and begged mother to let us go outside to play in the snow. She said we could go out after breakfast if we dressed ourselves warmly and promised to come back as soon as we felt cold. When we went out, the snow had almost stopped. The roads , paths, gardens, and playing grounds were all hidden under a white blanket of soft snow. It was the most beautiful sight we had ever seen. Just then, we saw some neighbour's children coming out to play. We ran over to join them. Together we built a snowman and a snow house. After that, we took turns sliding down a hill on a large piece of cardboard. We were having so much fun when supper time came. Mother almost had to force us to go in and eat.
Answer: it was the first time they had seen snow

Answer: The children all cheered when they saw the snow because _ .

Question: Article: *Share flats happy valley big flat, 1 room ready for use immediately. quiet and convenient, fully furnished, park view. $6, 800 including bills with maid. female nonsmoker. no pet. sara 25720836 or 10077809. * moving sale 2 armchairs, red/brown at $400 each; coffee table, black, wood, $800; oil painting, big, $900; tianjin carpet, green 3x7, $600; double bed, $500; mirror, big, square, $500; fridge, big, double-door, $1000; old pictures, $140, up, each; plants, big and small. tel: weekend, 2521-6011/weekday, 2524-5867. * part-time laboratory assistant wanted required by busy electronics company to help with development of computer. should have an electronics degree and some practical experience of working in an electronics laboratory. hours 9:30 a.m.-1:00 p.m. mon.-fri. fourteen days paid leave. salary Y=6598-Y=10230 dependent on experience. letter of application to: mrs. g chan, nova electronics, 45 gordon rd, hung hom kowloon.
Answer: find another lady to share the cost to rent a flat

Answer:
The one who put on the first ad probably wants to _ .