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.

Ex Input:
Article: If you look at the night sky, you'll often see stars moving very quickly. In fact, they move much more quickly than they should according to their size and the laws of physics. Scientists do not completely understand why the speed of these stars is so high. But many believe the reason is that much of the universe is made of something called "dark matter". Groups of stars called galaxies, such as the Milky Way, might even be made up of 90 percent dark matter. How much something weighs depends on where it is. The same object weighs only half as much on Mars as it does on Earth and almost three times as much on Jupiter. So scientists prefer to talk about the mass of something rather than how much it weighs, because mass does not change. They can work out the mass of galaxies by measuring the distance between them and the speed they move at. Recently, Jorge Penarrubia, a senior academic at Edinburgh University, UK, and his team discovered something interesting: The mass of the Milky Way is only half as much as the mass of another nearby galaxy, Andromeda. This seems strange, and dark matter may explain why. Finding out more about dark matter could help us understand how the universe began, but this is not easy. Lots of scientists with different types of expert knowledge are working on the problem. We can't see dark matter, it's very difficult to measure and we can't find out its mass. Unlike stars, dark matter doesn't produce or reflect light. But we can make a good guess that it is there because of the way things move and the way light bends. Experts now think dark matter may be very different from the matter that we find on Earth. There may also be five times as much dark matter in the universe as ordinary matter.
Answer: 7.5 kg; 45 kg

Ex Output:
Something that weighs 15kg on Earth weighs about _ on Mars and _ on Jupiter.

Ex Input:
Article: Cloud seeding is a method of artificially causing clouds to produce precipitation in the form of rain or snow.Cloud seeding has also been used in attempts to modify the severity of hail storms and hurricanes.The effectiveness of cloud seeding remains controversial .but it continues to be used in some regions to try to increase rainfall for agriculture and to build snow packs for water supplies and power production. Cloud seeding was developed by American scientists Irving Langmuir and Vincent Joseph Schaefer during and after World War II.Their work began as an effort to learn more about the buildup of ice on airplane wings, and eventually led them to attempt to create rainfall by releasing several pounds of crushed frozen carbon dioxide into a cloud from an airplane.In this form, the carbon dioxide is called dry ice.On November 13, 1946, the technique appeared to produce snow directly under the cloud; the snow then turned to rain as it fell to the ground. For their experiment, Langmuir and Schaefer selected a supercooled cloud, one in which the water droplets remain liquid in subfreezing temperatures.Their theory was that small grains of dry ice falling through the cloud would cause tiny droplets of water vapor in the cloud to freeze into crystals that attracted more water vapor.Their theory proved to be correct and eventually the crystals became heavy enough to fall from the cloud as snow.As the snow reached the warmer temperatures closer to the ground, it melted and became rain. Another scientist, Bernard Vonnegut, produced a method of cloud seeding using silver iodide .He used particles of silver iodide because its crystal structure resembled that of ice in clouds.Silver iodide also had practical advantages over frozen carbon dioxide It could be stored at room temperature and did not require an airplane as a delivery mechanism.Instead, silver iodide crystals could be fired by cannons high into the air, where wind carried them into the clouds.
Answer: it is similar

Ex Output:
Bernard chose silver iodide as a method of cloud seeding because _ .

Ex Input:
Article: "Please read this," my three-year-old Claire said one day, pointing to a page with an old children's song: "Do you know how to plant cabbages". In blue ink, someone had crossed out cabbages and written "Watermelons!" "Daddy! Did you do that?" Claire asked, looking up with an expression of shock. We had only recently asked her not to write in books, and suddenly here was proof that her parents weren't practicing what they asked. I told her it was written by my grandfather and sat down to tell the story. I grew up on Granddad's farm in Nebraska, America. One afternoon, I decided to plant some watermelons. "Hmm, there's a crop I haven't tried!" Granddad smiled. "Let's do it now!" With Granddad's help I planted the seeds. The next morning, I found a big watermelon there. I knew it was Granddad that put a watermelon there and I thought he had played a joke on me. Later that month, Granddad gave me a book. "For school," he said seriously. I opened it to where he'd written "Watermelons!" and laughed at another of his jokes. Claire listened quietly to the story and asked to plant seeds too, so I took her to buy some seeds. On the walk home, I realized for the first time that Granddad could have met my childish enthusiasm with some disappointing facts such as that watermelons don't grow well in Nebraska or that it was too late to plant them anyway. But instead of doing that, he had stolen back into town that afternoon and bought the biggest melon on the market. That night, after I was asleep, he had awkwardly unloaded it and, with a painful bend, placed it exactly above my seeds. He made sure I experienced the "wow." I had always thought the midnight miracle was just one of Granddad's jokes. Now I realized he had planted hope that day. As Claire planted the seeds happily, I watched my grandfather's joy take fresh root in her life. And that was the biggest miracle of all.
Answer: there should be a mistake in the book

Ex Output:
Claire was shocked at the mark on the page because _ .