题目

在①AE=CF；②OE=OF；③BE∥DF这三个条件中任选一个补充在下面横线上，并完成证明过程．已知，如图，四边形ABCD是平行四边形，对角线AC、BD相交于点O，点E、F在AC上， (填写序号)．求证：BE=DF．注：如果选择多个条件分别解答，按第一个解答计分． 答案：【答案】见解析【解析】若选②，即OE=OF；根据平行四边形的性质可得BO=DO，然后即可根据SAS证明△BOE≌△DOF，进而可得结论；若选①，即AE=CF；根据平行四边形的性质得出OE=OF后，同上面的思路解答即可；若选③，即BE∥DF，则∠BEO=∠DFO，再根据平行四边形的性质可证△BOE≌△DOF，于是可得结论．解：若根据短文理解，选择正确答案。The timer is running. These people have 60 minutes to escape (逃脱) from a room they paid to be locked inside.It is a game with clues (线索) that are spread in the room. And there is no starting point. You start wherever you feel like. It is up to you to put the clues together in order to find the key to get out.A popular room offered by Timothy Smith in Washington D.C. is designed to mimic (模仿) the Oval Office in the White House. It is built like the office of the American president. The fun part of Escape the Oval Office is that anything here could be a clue to solving the puzzle. An old typewriter from the 1930s. Or the small table in the corner. Or the map of Washington D.C. on the wall. And then there are hidden messages that can only be seen under a black light.Sometimes, the telephone rings. “Would you guys like a clue?” The boss controls the game progress on a camera and calls to offer hints (提示) when needed.Teams can be made up of classmates, families, tourists, or a group of six friends and two strangers who just meet before the game starts.It's said that there are more than 800 Escape Room adventures in Washington D.C.. Each experience has different themes and stories. The rules for playing are similar, and solving the puzzle needs social, physical abilities and quick, creative thinking.It was a little stressful. Some of the clues seemed really complex (复杂的). But it was a lot of fun, and the players had no idea what to expect. Escape Room adventure is popular because it gives any person a chance to be a detective or to be a James Bond. However, like most team sports, this game is really all about being a good teammate and having a good time.（1）Escape the Oval Office is a popular room in __________ .A.ChongqingB.Washington DCC.BeijingD.Hong Kong（2）The underlined word in the last paragraph means __________ .A.侦探B.律师C.医生D.政客（3）Which of the following is TRUE according to the passage?A.All game clues are easy to find.B.Nobody can give any hints during the game.C.Strangers can't play the game together.D.Players need to work together to escape successfully.（4）This passage is probably from a(an) _____________.A.newspaperB.medicine boxC.story bookD.movie poster