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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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Article: April Fool's Day , was a day of laughing and jokes. This day is kept in many countries, not only in Britain and the USA. This is a day to play jokes and make people laugh. Nobody knows when was the beginning of this custom. Some people connect it with the end of winter and the return of spring which make people merry and ready to play jokes. In Scotland young people were sent for hen's teeth or bird's milk and everybody laughed when they could find such things. In the USA and Britain some people could place a sign on a person's back with the words "push me!" Children often tell a grown-up that his sock is torn or he has something black on his face, and then shout "April Fool!" There is also the old purse trick. A purse is left lying in the street, but when someone wants to take it, it is quickly pulled back by a string which the hidden joker holds in his hand. Or the purse may be filled with stones. Sometimes invitations are sent to people, asking them to come and visit somebody, but when they come they see that nobody expects them. Some people like to telephone to the zoo on the day and ask for Mr. Fish, Miss Fox or Mrs. Cat. All these jokes are very old but still they make people laugh.
Answer: Someone
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_ knows when the custom of April Fool's Day started.

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Article: The 32ndHong Kong Art Festival,to be held early next year,will be based on the theme of "family". The art festival, considered to be Asia's best, began in 1973. "We hope that people from Beijing and from all over the world will go to Hong Kong to enjoy the multiple performances in our art festival," Douglas Gautier, the festival's management director, said in a press conference in the capital. In the 29 days of the festival, which runs from February 8 to March 7,2004, the audience can choose from 111 performances of 51 programmes staged by 700 foreign performers,450 local artists and 160 actors from the mainland. Programmes vary from classical music, jazz, world music, Western and Peking opera, drama and dance to outdoor spectaculars. The programmes include Beethoven's only opera Fidelio, Shakespeare's drama Romeo and Juliet, the ballet Mozartina and African dances, to name just a few. The lineup includes the English Touring Theatre, Prague Chamber Orchestra, Zurich Ballet, the Spanish National Dance Troupe, as well as Europe Galante the Petersen Quarter, pianists Angela Hewitt and Marc-Andre Hamelin, and saxophonist Jan Garbarek. In an effort to increase attendance, hotels and airlines are offering _ along with art festival ticket sales, most of which are at 20% and 30% discounts. For more information, please check: _
Answer: in England
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The press conference must have been held _ .

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Article: A safari park is a park in which wild animals are kept. They are mainly located in east or central Africa. They often occupy a very wild area, with mountains and rivers. To visit the park and look at the animals, people have to drive around in a car for a few of hours because the park is huge. In south Africa there is a safari park, which contains all sorts of wild animals like lions, elephants, rhinoceroses, zebras, wild pigs, deer and giraffes. There is a wild road leading through the park, but nobody is permitted to walk on the road. Anyone traveling in the park has to go in a car because wild animals may fiercely attack people. From the car he may see almost every types of African wildlife. Some of these are getting rare because people kill them for various reasons. For example, rhinoceroses are killed for their horns, which are used in traditional Chinese medicines for colds and headaches. Perhaps they will be seen only in museums and books one day. Travels may purchase food for the animals. They can feed them when they tour the park. Of course, they should not feed them in a close distance because the wild animals may attack people. In addition, they should only give proper food to the animals. A traveler may carry a gun with him in his journey. The gun is given to him by the government. However, it is not used for hunting. In fact, a seal is fixed to it. The traveler may fire at a wild beast to defend himself in case he is attacked. However, he has to prove to the government that he has been attacked and that he has not fired at a harmless animal.
Answer: stay away from the animals
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When travelers feed the animals, they should _ .