请以“动物”为话题写作文，题目自拟，除诗歌外文体不限，不少于600字。

下列用途不属于氮气用途的是（　　）

根据短文理解，选择正确答案。

    “Cool” is a word with many meanings. Its old meaning is used to express a temperature that is a little bit cold. As the world has changed, the word has had many different meanings. “Cool” can be used to express feelings of interest in almost everything.

    When you see a famous car in the street, maybe you will say. “It's cool.” You May think, “He's so cool,” when you see your favorite football player.

    We all maximize(扩大)the meaning of “cool”. You can use it instead of many words, such as “new” or “surprising”. Here's an interesting story we can use to show the way the word is used. A teacher asked her student to write about the waterfall(瀑布) they had visited. On the student's paper was just the one sentence, “It's so cool.” Maybe he thought it was the best way to show what he saw and felt.

    But the story also shows a scarcity(缺乏)of words. Without “cool”, some people have no words to show the same meaning. So it is quite important to keep some credibility(可信度).Can you think of many other words that make your life as colorful as the word “cool”? I can. And I think they are also very cool.

秦始皇是一个有争议的历史人物，阅读下列关于秦始皇的材料：

材料一：“廿六年（公元前221年），皇帝尽并兼天下诸侯，黔首（全国）大安，立号为皇帝”。

材料二：“分天下以为三十六郡，郡置守、尉、监”。

材料三：“一法度衡石丈尺”。

材料四：“烧来经书，涤除旧典，大发隶卒，兴役戍……”坑杀儒生和方士。

请回答：

雄安新区规划范围涉及河北省雄县、容城、安新三县及周边部分区域，地处北京、天津、保定腹地，区位优势明显，交通便捷通畅，生态环境优良，资源环境承载能力较强，现有开发程度较低，发展空间充裕。规划建设雄南新区的重点任务是：建设绿色智慧新城，建成国际一流、绿色、现代、智慧城市；打造优美生态环境，构建蓝绿交织、清新明亮、水城共融的生态城市；发展高端高新产业，积极吸纳和聚集创新要素资源，培育新功能；提供优质公共服务，建设优质公共设施，创建城市管理新样板；构建快速高效交通网，打造绿色交通体系；推进体制机制改革，发挥市场在资源配置中的决定性作用和更好发挥政府作用，激发市场活力；扩大全方位对外开放，开放创新高地和对外合作新平台。

结合材料，说明规划建设雄安新区对推动京津冀协同发展的经济意义。