题干

已知BD垂直平分AC,∠BCD=∠ADF,AF⊥AC,

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同类题1

阅读下面文章,完成第1~4题。

鹦哥岭

1鹦哥岭位于海南省中南部,具有热带雨林面积大、生物物种丰富、原始性强等特点,是我国原始热带雨林中保存最完好的自然保护区,在我国自然保护区体系中有着不可替代的作用。

 2___________________。据调查发现,鹦哥岭保存着我国面积最大的、连片的原始热带雨林,其面积有250多平方公里,而被评为中国最美森林的尖峰岭,其连片的热带雨林也仅为150平方公里,霸王岭、吊罗山、黎母山、五指山则更低。

3 ___________________。据调查,鹦哥岭的物种非常丰富,有国家一级重点保护植物5种,二级17种,海南特有物种植物132种;陆栖脊椎动物431种,其中,国家一级重点保护动物4种,二级36种,51种列入中国濒危。在调查中,专家们还不断发现新的物种,如首次发现的伯乐树、鹦哥岭树蛙等十多种动植物新种。专家们认为,鹦哥岭可能还存在着大量未认识的物种。

4_____________________。考察我国热带雨林保护区,包括西双版纳、尖峰岭、霸王岭均在历史上或多或少建立了森林开发利用机构,而鹦哥岭由于山高坡陡,交通闭塞,人烟稀少,绝大部分区域从未有过正规和大规模的开发利用,表现出非常明显的原始特征,有许多地方还从未有过人类足迹,是我国非常少有的一块热带雨林处女地。

 5鹦哥岭是海南岛两大河流——南渡江、昌化江的发源地和水源涵养林,主宰着海南岛的水系形态。鹦哥岭还是海南第二高峰,其森林与地形地貌影响着海南全岛气候,一旦森林植被遭到破坏,将从根本上影响海南岛整体气候,使本岛大部分地区的农业生产遭到毁灭性的打击,后果堪忧。

6近年来,鹦哥岭的知名度越来越高,但随之受到的威胁也越来越严重,乱伐、盗猎等现象时有发生。2007年以来,27名青年大学生志愿者陆续奔赴鹦哥岭,开始了自然保护区的工作,并一直坚守岗位至今。鹦哥岭自然环境的保护工作是长期而艰巨的。让我们都行动起来吧!鹦哥岭在呼唤!

                                        (选自《大百科》有删改)

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同类题4

语法填空

    Henry was an office____(work) in a big city. He worked very hard and enjoyed traveling in his holidays.

    He usually went to the seaside, but one year he saw____advertisement in a newspaper. “Enjoy country life. Spend a few weeks at West Hill Farm. Good food, Fresh air, Horse riding, Walking, Fishing, cheap and interesting.” “This ____(sound) a good idea,” he thought. “I'll spend a month at West Hill Farm. I think I can enjoy horse riding, walking and fishing. They'll make a change from ____(sit) by the seaside and swimming.”

    He wrote to the farmer. In the letter he said that he would like to spend all of July there. Then on the first day of July, he left ____West Hill Farm.

But four days later, he returned home.

    “What was wrong ____West Hill Farm?” his best friend, Ed, asked him.

    “Didn't you enjoy country life?” “Country life was very good,” Henry said.

    “But there was another problem.”

    “Oh. What?”

    “Well,” he said, “the first day I was there a sheep died, and we had roast mutton for dinner.”

    “What's wrong with that?” Ed asked. “Fresh meat is the best.”

    “I know, but on the____(two) day a cow died, and we had roast beef for dinner.”

    “How ____(luck) you are!”

    “You don't understand,” Henry said. “On the third day a pig died and we had roast pork for dinner.”

    “A different meat every day,” Ed said____(loud), “and what are you complaining!”

    “Let me finish,” Henry said. “on the fourth day the farmer____(dead), and I didn't dare (敢) stay for dinner!”