题干

从化学键的角度看,化学反应的实质是“旧化学键的断裂和新化学键的形成”,下列变化中既有旧化学键断裂,又有新化学键形成的是
 

A:酒精溶于水

B:二氧化碳变成干冰

C:CaO作为干燥剂吸水

D:氯化钠受热熔化

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答案(点此获取答案解析)

C

同类题4

阅读理解

Some years ago, writing in my diary used to be a usual activity.I would return from school and spend the expected half hour recording the day'sevents, feelings, and impressions in my little blue diary. I did not reallyneed to express my emotions by way of words, but I gained a certainsatisfaction from seeing my experiences forever recorded on paper. After all,isn't accumulating memories a way of preserving the past?

When I was thirteen years old, I went on a long journey on footin a great valley, well equipped with pens, a diary, and a camera. During thetrip, I was busy recording every incident, name and place I came across. I feltproud to be spending my time productively, dutifully preserving for futuregenerations a detailed description of my travels. On my last night there, Iwandered out of my tent, diary in hand. The sky was clear and lit by the glareof the moon, and the walls of the valley looked threatening behind their screenof shadows. I automatically took out my pen...

At that point, I understood that nothing I wrote could evermatch or replace the few seconds I allowed myself to experience the dramaticbeauty of the valley. All I remembered of the previous few days were the dullcharacterizations I had set down in my diary.

Now, I only write in my diary when I need to write down aspecial thought or feeling. I still love to record ideas and quotations thatstrike me in books, or observations that are particularly meaningful. I takepictures, but not very often only of objects I find really beautiful. I'm nolonger blindly satisfied with having something to remember when I grow old. Irealize that life will simply pass me by if I stay behind the camera, busypreserving the present so as to live it in the future.

I don't want to wake up one day and have nothing but a pile ofpictures and notes. Maybe I won't have as many exact representations of peopleand places; maybe I'll forget certain facts, but at least the experiences willalways remain inside me. I don't live to make memories--I just live, and thememories form themselves.

同类题5

阅读下面的文字,完成后面题。

    我国领导人访问非洲,接受的最高礼遇是舞蹈夹道欢迎。其实世界各国许多重大外事活动,也常使用不同的舞蹈方式。它跟三军仪仗队一样,其内涵都包含一种国力或文化的炫耀。舞蹈代表这个民族早在人类语言没有产生前的文化成就。凭借舞蹈原始遗存,一些人类学家、哲学家们达成一个共识:“舞蹈是人类一切艺术之母。”

    舞蹈虽然很古老,但其文化意义却常遭到误解。当代美国符号美学家苏姗·朗格说:“没有任何一种艺术,比舞蹈蒙受到更大的误解、更多的情感判断和神秘主义解释了。”舞蹈是一种非语言艺术,也是非文字文化。但人们在认识或评价它时却用语言艺术或文字艺术的标准来判别,这样就会张冠李戴。如同艺术史家约瑟夫·马库利斯所说:“在综合性美学观点的评述中。要么几乎从不提及舞蹈本身的艺术特性,要么就是硬性地或直接基于其他门类艺术的立场。”

    舞蹈的感性材料是人自体,这是舞蹈与其他艺术文化最重要的区别。即使其他与人体有关的艺术,在作品完成后,作品与人都可分离,唯人体与舞蹈永不分离。真正的舞蹈不是说的也不是理论的,而是由人跳出来的。这便决定了它必定具有鲜活性、现场性,表演时故在,表演结束舞蹈随即消失。因此,古代舞蹈很难真实地保存下来,现代虽可通过影像设备做记录,但它已不是舞蹈家作品,而是摄影家的作品了。

    舞蹈是人体艺术,主要是通过人体动作、动态来表达人的情感、思想和情绪。它的接受也不依赖语言,或主要不依赖语言。那么靠什么呢?意会。人们常说优秀的舞蹈“只能意会。不能言传”,在舞蹈家看来,最美的舞蹈用语言说不清楚,即使能说出来,也会变得不仅词不达意而且浅白而失却生动性。因此全世界的舞蹈家都不喜欢用嘴巴去诠释自己的舞蹈,即使节目单要写上几句暗示的话,他们也尽可能采取很抽象的语言。这当然也会带来误解,以为舞蹈家没理论,或不善理论。不善理论可能是对的,因为舞蹈家最善于用肢体说话,但不等于没有理论,只是这种理论也不是语言性理论。口头语言或文字确实不能准确说清舞蹈,文字理论在舞蹈面前永远是灰色的,第二位的。人类发展舞蹈理论,只不过是让它帮助人自己加深与舞蹈本体的接近罢了。

    上演了一百多年的芭蕾舞小品《天鹅之死》,没人问它到底要说什么,也无人怀疑人体到底像不像天鹅,作品在讴歌生命的这一深层内涵,即使说不出来,也不愿用“天鹅临死不想死,好死不如赖活着”的话来浅白它。常人白话会砧污作品的美,优秀舞蹈的思想内涵所具形而上的哲理,需给予深层意会。

    中国当代古典舞《扇舞丹青》,人人都喜爱,人人都能感受到它那传统美的意味。如非要问表演的是谁?她在干什么?她在什么地方?她是文人才女还是画家手中的笔.她是色彩还是线条……不要说编导抑或演员无可回答,任何人都会觉得这种发问不正常。该舞获了那么多奖励,久演不衰,被行内外普遍认可,也是在意会作用下的接受。(摘编自吕艺生《舞蹈文化面面观》)