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某班同学用如下实验探究Na2CO3、NaHCO3的性质.回答下列问题:
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同类题2

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    There is no doubt that the first day of school can be crazy for most of students. New kids wander (徘) around in circles, waiting for the opening of the school door. The school nurse needs your medical records. ____ The freshmen are running in all directions, looking for their new classrooms.

    How can you overcome the first-day chaos? If you will go to a new school, try to arrange a visit before classes begin. Explore any areas, such as the playground, library, or school labs.____

    Get one and read it before your school, starts-then keep it in your school bag until you're familiar with your new surroundings. Your first day is also the time to bring in school supplies and books.

    You should arrange your schoolbag well the night before you go to school so that you won't look for what you need at the last minute.

    Did you try on eight different coats before deciding on what to wear?____ The best choice is to wear what makes you feel good, whether it is a new coat or an old sweater. If you plan to wear a pair of shoes, make sure they fit you well.

    ____ Some start with a gathering, while others may jump right into the first-period class. You'll meet your new teachers, and they will probably give you an overview of the courses, class rules, what the semester will be like, what supplies you'll need, and expectations of your performance and behavior. Some teachers will jump into their first lesson, while others may have some activities.____

A. Some schools even offer maps.

B. But you forget to bring it with you.

C. It all depends on the class and teacher.

D. Don't depend on your parents any more.

E. Each school has different opening-days.

F. You can also try to ask the teachers for help.

G. Lots of students have difficulty deciding on what to wear on the first day of school.

同类题5

阅读下面的文字,完成下列各题。

    如今,大家一提工匠精神,一般都先想起德国、日本等发达国家。殊不知,自古以来,工匠精神就是“中国气质”之一。中国自古就是一个具有创新传统和工匠精神的国度。工匠在古代的社会地位不算高,但有很多匠人名垂青史。先秦的鲁班、李冰是以心灵手巧而成就事业的标杆人物。明朝的宋应星撰写的《天工开物》,被外国学者誉为“中国17世纪的工艺百科全书”。中国古代各类手工匠人以精湛的技艺为社会创造价值,做出过不少重要的发明和创新,为中华文明的形成与繁荣做出了不可或缺的重要贡献。工匠们往往以打造精品为追求。例如,早在6000多年前,中国人开始制作玉器。朱熹对《论语·学而》中的“如琢如磨”做了注解。他说:“治玉石者,既琢之而复磨之;治之已精,而益求其精也。”这是中国思想家对工匠精神的精彩解说。

    其实,在工业化早期阶段,德国生产的产品根本谈不上精致。德国人到英国展出产品,被要求标注:“Made in Germany”,相当于劣等产品的标签。这种标注产地的做法给德国人以很大刺激。他们立志要摘掉劣等产品的帽子,经过上百年努力,才后来居上,使“Made in Germany”成为精品的标记。曾几何时,“东洋货”也曾是劣质产品的代名词,现在日本产品却大都是世界精品。

    精品的产出,当然需要制度作保障。比起标注“Made in Germany”,中国很早就形成了标注制造者姓名的制度。秦始皇统一了度量衡,为控制产品质量,推行标准化生产奠定了基础。在秦始皇统一中国之前,秦国就实行了“物勒工名”制度。以方便管理者检验产品质量、考核工匠的技艺。据《吕氏春秋》记载,“物勒工名,以考其诚,工有不当,必行其罪,以穷其情。”《秦律》中也有许多具体的惩罚规定。秦代制器,不仅要刻上工匠之名,还要刻上督造者和主造者之名,以便逐级追查产品质量的责任人。如果不刻写名字,就要被罚款。

    秦朝还建立了从中央到地方的系统的技术与产品质量管理机构,及分工负责制度。以少府为例,工师为手工业作坊的负责人,集技术与管理于一身,还传授技艺,监督工匠操作、产品质量检验等。检查产品质量,要求“必功致为上。”(《吕氏春秋·孟冬纪》)。做得好的,也有具体的奖励办法。由于有这样的制度,我们就不难理解,为什么秦朝能够制造出精湛的铜车马、兵马俑等艺术品。

    在中国历史上,工匠制度的传承发展,渐渐形成了特有的工匠文化和工匠理念,对工匠的行为有很强的约束力。以瓷器工匠为例,官窑(如龙泉窑)生产的好产品呈给皇家,出现次品就要砸掉。陶瓷界有实力的厂家都坚守一个传统:仿品不能当正品出售。正是有“精益求精”的精神、有制度作保证,中国历朝历代才能不断产出名扬四海的精品,如玉器、青铜器、瓷器、丝绸等,铸就东方文明古国的灿烂文化。

    今年以来,工匠精神之所以成为全社会广泛关注的热点话题,是因为它切中时弊、符合时需。在当代中国产业界和其他行业都应当弘扬,或者说找回中国工匠“精益求精”的精神,全社会也要尊重能工巧匠的创造力和贡献,使“Made in China”成为精致美好、质量信得过的标签。

(摘自《光明日报》《工匠精神自古就是“中国气质”》)