题干

某温度时,将20g KNO3溶解在100g水中恰好饱和,关于该饱和溶液的叙述正确的是(  )

A:m(溶质):m(溶剂)=20:120

B:溶质的质量分数为20%

C:升温后,溶质的质量分数增大

D:降温后,有固体析出

上一题 下一题 0.0难度 选择题 更新时间:2011-02-21 05:18:33

答案(点此获取答案解析)

D

同类题1

阅读以下上栏人员在生活和学习中遇到的问题,然后与下栏所提出建议相匹配

____I'm always late for school. I try not to be, but I can't. Please advise me what to do.

____I lived with my grandparents for many years. Three years ago I began to live in my school far away from my parents. They love me. But I don't know how to show my love to them. What can I do to let them know I also love them?

____I'm one of the best students in my class. But I always make some mistakes that I should not make. And now, I'm afraid to see my teachers. I just don't know how to face them. Can you tell me what I should do?

____I don't like today's life. It's just work, work and work. I work hard day by day. How bored and tired I feel!

____ My English is very poor. I am weak in writing composition(作文). I don't know how to improve it.

A. The first thing you need to do is to relax. If you have any difficulties, tell your teachers. No teacher is going to get angry with a student who wants to improve himself.

B. If you want to show your love to your parents, that's great. Make sure you remember their birthdays and buy them cards and gifts. Try to enjoy your life. Your parents want you to be happy. If you are happy , they will be happy, too.

C. You are late for school probably because you go to bed too late. I advise you to go to bed earlier and buy a clock to wake you up.

D. If you want to give your friend a big surprise, you can do something else for her rather than giving her a present. You are a student and haven't enough money to buy something expensive.

E. Don't complain. If you feel tired of work, you can go to parties or just relax. Remember this saying: All work and no play makes Jack a dull boy.

F. You should read more and recite(背诵)some good compositions. Try to write a diary in English everyday. I am sure you will improve your English by doing these things.

G. You should tell your friend that he has done something wrong. Cheating(说话) in exam is not a right thing that we should do.

同类题4

阅读下面的文字,完成小题。

慎终追远  清明永驻

    清明节大约起源于周代,至今已有两千五百多年的历史了。最初,清明只是一个提醒农民进行春耕春种的节气。《淮南子·天文训》记:“春分后十五日,北斗星柄指向乙位,则清明风至。”《岁时百问》云:“万物生长此时,皆清洁而明净,故谓之清明。”清明时节,我国大部分地区气温升高,雨量增多,正是春耕春种的大好时节,故有“清明前后,种瓜点豆”“清明谷雨紧相连,浸种春耕莫迟延”等农谚。这种标志物候变化、敦促春耕的节气,是怎样变成以祭奠祖先为中心的综合节日的呢?

    首先,这与清明前两天的寒食节有关。相传,寒食节起源于春秋时期的晋文公、介子推一段动人的故事。但当代学者普遍认为,寒食节与古人对于自然的认识相关。他们认为世界万物都和我们人一样是有生命的,也有生老病死,需要新陈代谢。火燃久了要熄掉,重取新火。寒食之后重生新火就是一种辞旧迎新的过渡仪式。熄灭旧火与重生新火所透露的是季节交替的信息,意味着新的一年春耕生产的开始。寒食节在清明前两日,寒食禁火冷食祭墓,清明取新火踏青出游。唐代之前,寒食与清明是两个前后相继但主题不同的节日,一为怀旧悼亡。一为求新护生;一阴一阳,一息一生。二者有着内在的文化关联。

    清明节也融合了上巳节的一些习俗。上巳节俗称三月三,它形成于春秋末期。时至唐代,上巳节成了一个全国性的节日,人们常在此日到水边嬉戏,去郊游踏青。后来,上巳节的踏青饮宴的特点被整合到了清明节的习俗之中。清明节发展最盛的时期是宋代。北宋孟元老的《东京梦华录》载:“寒食第三日,即清明节矣,凡新坟皆用此日拜扫,都城人出郊,四野如市,往往就芳树之下或园囿之间,罗列杯盘,互相劝酬。都城之歌儿舞女,遍满园亭,抵暮而归。”可见,宋人借祭祖扫墓的机会充分享受踏青之乐,寓嬉乐于哀痛之中。张择端绘制的风俗画长卷《清明上河图》更是形象地呈现出宋代清明节的盛况。到了元代,不仅上巳节退出了节日传统,寒食节也已基本消亡。春节之后的大好春季只剩下了清明节。

    清明节祭祖扫墓、追念先人功德的活动,与中国深层的祖先崇拜、孝文化传统之间有着深刻的联系,而这种文化传统正是中国社会几千年来得以和谐稳定发展的支柱,也是清明节具有强大生命力的民间根基。随着民族精神的复兴,对祖宗的家族性私祭发展到对中华民族共同祖先黄帝、炎帝的群体性公祭,以延续中华民族血脉相连、薪火相传的精神,这些都抒发了人们慎终追远、明德归厚的道德情怀。

    中华传统节日是民族生活的仪式,是弘扬中华民族优秀文化和传承中华美德的重要载体。现在我们过清明节,就是一次对中华民族优秀文化感悟和认同的过程,就是要通过扫墓祭祀等形式唤起后人对祖先的追思与敬慕,全面体现对祖先的感恩、对血脉责任的认同,确保我们民族的优秀文化和共同记忆,得以代代相传、万载永续。

(节选自李荣启《感悟清明节的文化内涵》,有删改)