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

Example Input: Article: There are many places around the city and online to buy Las Vegas show tickets. With dozens of websites you can find at home, ticket box offices, Tix 4 Tonight (one of the two half-price ticket sellers) locations, and ticket sellers along the Las Vegas trip, you might wonder where you could find your best deal. Major Shows If you want to see one of the top shows in Las Vegas, you could buy your tickets online before your trip. Many of these shows sell out months ahead of time, so make sure you do your research. Best Place to Buy Discounted   Tickets If you want discounted tickets for Las Vegas shows, you should go to one of the four Tix 4 Tonight locations. These locations get tickets early in the morning or throughout the day if shows are not sold out. Do not expect to find discounted tickets here for the hottest shows in town such as one-night concerts or shows like Celine Dion's. These seldom make their way to Tix 4 Tonight. Coupon books   As you walk along the Las Vegas Strip, you are going to come across people handing out the Vegas Values coupon books or other coupons. These may help you find discounted coupons for various shows around town. Tickets bought with coupons have to be bought at the box office for the show. These are usually located near the theater used for the show. On-Strip Sellers If you see people standing on the Strip selling show tickets, make sure you avoid them. While a few of these sellers might be legitimate  ,they often cheat people by selling counterfeit   tickets. Catching a show in Las Vegas is one of the various activities people take part in every single day. While there is not one set place to be the best to buy tickets, make sure you get to see the show you want. 
 Answer: through online shopping
Example Output: If you want to see Celine Dion's performance, you should buy the tickets   _  .

Example Input: Article: ADDIS ABABA, Ethiopia - One of the world's most famous fossils   - the 3.2 million-year-old Lucy skeleton   unearthed in Ethiopia in 1974 - will go on an exhibition tour abroad for the first time in the United States, officials said Tuesday. Even the Ethiopian public has only seen Lucy twice. The Lucy on exhibition at the Ethiopian National Museum in the capital, Addis Ababa, is _ while the real remains are usually locked in a secret storeroom. A team from the Museum of National Science in Houston, Texas, spent four years discussing with the Ethiopians for the U.S. tour, which will start in Houston next September. "Ethiopia's rich culture of both the past and today, is one of the best kept secrets in the world," said Joel Bartsch, director of the Houston museum. The six-year tour will also go to Washington, New York, Denver and Chicago. Officials said six other U.S. cities may be on the tour. But they said plans had not been worked out. Travelling with Lucy will be 190 other fossils. Lucy, her name taken from a Beatles song that played in a camp the night of her discovery, is part of the skeleton of what was once a 3-foot-tall ape-man  . 
 Answer: report a coming event
Example Output:
The author writes this text mainly to   _   .

