题干

在下面一段文字①②③处补写恰当的语句,使整段文字语意完整连贯,内容贴切,逻辑严密, 每处不超过12个字。

在人类文明进程里,城市的产生和发展是关键的一步。一般而言,城的发展往往早于市。,城墙、堡垒、护城河构成防御设施,封闭是其主要特征。市的功能主要是流通,交易场所、街道是主要设施,,反映了由军事和政治意义的城镇向现代的经济、文化为主的城市的发展走向。

上一题 下一题 0.0难度 选择题 更新时间:2018-08-19 12:08:25

答案(点此获取答案解析)

①城的主要功能是防御

②开放是其主要特征

③从城到市的变化(或“从封闭走向开放”、“从防御趋向流通”)

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    A 15-year-old student who invented a flashlight(手电筒) getting power from the holder's body heat is going home today from California with a big prize and a chance to do further research.

    Ann Makosinski was the only Canadian among the four winners at Google's international science competition. Thousands of young scientists from around the world took part in the competition.

    Winning the science and technology competition was "a surprise". Ann said, "I think it will have a great influence on my future."

    Ann thanked her family for encouraging her interest in science and said that her first toy was a box of transistors(晶体管).

    Ann's prize includes $ 25,000 and a "once in a-lifetime expericnce" from Google for her Hollow Flashlight, which has no moving parts or batteries.

    The idea for the invention came from seeing unwanted batteries and her friend's experience. When Ann visited a friend in the Philippines, she saw the friend couldn't study when it became dark because there was no electricity or light. She saw the need for a flashlight that has no batteries - Hollow Flashlight.

    In her project, Ann wrote "I made two flashlights that do not use any batteries or harmful materials. They do not create any noise and will always work. The flashlight needs at least a 5℃ temperature difference between the holder's body and the environment around to produce light."

    A video of Ann explaining how she creatcd the flashlight has been watched more than 1.4 million times on the Internet.

    Though Ann was successful, she has not made a decision about her career path. Ann hopes that she can find a way to join her love of film and science together.

    The four winners were chosen from 15 final competitors from eight countries. The competition attracted thousands of students in 120 countries.