完形填空题， 共15小题，通读下面的短文，掌握其大意。 然后，从每小题的四个选择项中选出可填入相应空白处的最佳选项。
　　Recently, some scientists decided to find out what the funniest joke in the world was. This wasclearly a (an)___21___task,as no two people ever really agree about what is funny and what is not___22___when they are from different___23___.
　　Telling jokes is something people often___24___around the world.___25__, jokes are sometimes not funny to or are often not___26___by people who are not part of that culture(文化).
　　Anyhow,___27___a year-long serious study, the scientists___28___the funniest joke in the world :Two hunters (猎人) are out in the woods. One of them___29___to the ground. He doesn't seemto be___30___, his eyes closed. The other hunter takes out his phone and calls emergency (紧急)services. "My friend is dead!"he___31___to the man on the other side. "What can I do?"The man,in a(an)___32___voice,says," Dont't worry. I can___33___. First, make sure he's___34___. "There isa silence,then a shot is___35___. Bang! The hunter's voice comes back on the line. He says," OK,now what?"