问题 填空题

用化学用语填空:

(1)地壳里含量最多的金属元素是______;(2)3个氢分子______.

(2)白酒中的溶质是______; (4)碱溶液中的阴离子______.

答案

(1)地壳中含量最多的金属元素是铝,该元素的符号是:Al;

(2)根据分子的表示方法:正确书写物质的化学式,表示多个该分子,就在其化学式前加上相应的数字,因此3个氢分子表示为3H2

(3)白酒是酒精的水溶液,溶质是酒精,该物质的化学式是:C2H5OH(或C2H6O)

(4)碱中的阴离子是氢氧根离子,离子的表示方法:在表示该离子的元素符号右上角,标出该离子所带的正负电荷数,数字在前,正负符号在后,带1个电荷时,1要省略.若表示多个该离子,就在其元素符号前加上相应的数字,则氢氧根离子可表示为:OH-

故答案为:

(1)Al

(2)3H2

(3)C2H5OH(或C2H6O)

(4)OH-

材料分析题

阅读下列材料,完成下列问题。

近30年来,我国人口增长过快的问题得到了有效的控制,人口出生率、自然增长率分别从1970年的33. 43‰和25.85‰,下降到1999年的15. 23‰和8.77‰。我国育龄妇女初婚年龄从1970年的20.8岁变化为1998年的23.57岁。我国平均家庭规模从1991年的4.84 人变化为1998年的3.63人。

(1)试分析我国育龄妇女初婚年龄逐年推迟的原因。 

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(2)试分析近30年来我国育龄妇女初婚年龄变化与我国人口数量的关系和原因。 

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(3)试分析我国家庭平均规模近30年来逐年缩小的原因。

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(4)从以上材料及问题的角度,试分析环境对人口数量变化的影响。

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阅读理解

Jealousy is a very common problem in daily life. It’s everywhere. For example, if someone does better than you, you will get annoyed because you want to be No. 1. We may become jealous of a best friend’s top marks in an exam, or of the girl in art class who is praised by the teacher all the time. We get annoyed because these good things are happening to someone else but not to us.

It’s bad to feel jealous. We should be pleased with the things we have. But we still wish we had the money of this person and the talent of that person. Instead of sharing their happiness, we just feel jealous and unhappy with ourselves. And, too often, these feelings are expressed by speaking ill of the people we envy.

However, envy is also a kind of compliment to others. We see that other people have styles and talents different from our own. By comparing ourselves with others, we can know what we lack. And we can turn this comparison, the envy of others, into a kind of power.

Therefore, being a bit jealous of others lets us know what we are like and what we want to be like. It can push us to become what we really want to be.

根据短文内容,从A、B、C、D四个选项中选出能回答所提问题或完成所给句子的最佳答案。

小题1:According to the first paragraph, why do you get annoyed?

A.Because the teacher dislikes others.

B.Because others do something better than you.

C.Because you are an annoying person.

D.Because you want to be No.1 in the exam and you do.小题2:The Chinese meaning of the underlined part “speaking ill of” probably is “_____".

A.赞美

B.说…的坏话

C.憎恨

D.说…病了小题3:What should be the right attitude towards jealousy?

A.It’s a good thing.

B.It’s just a bad thing.

C.It’s a kind of compliment to others.

D.It makes us know what we are like and what we want to be like.