试题与答案

我国人口现状的基本特点是 ( ) A.人口基数大、素质差 B.人口基数大、新增人

题型:选择题

题目:

我国人口现状的基本特点是 (    )

A.人口基数大、素质差

B.人口基数大、新增人口多、人口素质偏低

C.人口多、老龄化

D.人口数量大、分布不均

答案:

答案:B

题目分析:我国人口现状的基本特点是人口基数大、新增人口多、人口素质偏低,一般特点是农村人口多,人口老龄化速度加快,人口分布不平衡,男女性别比例失衡,因此B是正确的,A的说法是错误的,CD选项中既有基本特点,又有一般特点,所以排除,故选B。

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题型:完形填空
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Eating habits (习惯) are different in different countries. The Chinese have a saying “Eat good things for breakfast, eat a big meal for lunch, but eat less at dinner.” Many Americans agree that one should start the day with a good breakfast, but their ideas about lunch and dinner are different.
Most Americans only give themselves a short time for lunch. So they eat a small lunch. After work they will have more time to eat a big dinner. Also a quiet dinner at home with all the family talking about their day is a way to take a good rest after a long, hard day of work.
Eating at restaurants is also different. In China, people like to talk and laugh while eating. Very often you can hear people talking and laughing loudly, and they are just having a good time. In America it is not like this. They want a quiet place where they can eat a good meal far away from the noises of the outside world. If someone is talking too loudly, the manager (经理) of the restaurant will look at him or her angrily. If some people are talking too loudly, the manager of the restaurant may come out and ask them to be quiet.
The title (标题)of the text
小题1:                                                                                                              
Chinese
Americans
小题2:                   for breakfast.
Start the day with a good breakfast.
Eat a big meal for lunch.
小题3:                                                                 
小题4:                     at dinner.
Prefer a big dinner at home or restaurant.
小题5:                              
while eating at the restaurant.
Like to eat far away from the noises.
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题型:填空题

(16分)A、B、C、D、E为短周期元素,A~E原子序数依次增大,质子数之和为40,B、C同周期,A、D同主族,A、C能形成两种液态化合物A2C和A2C2,E是地壳中含量最多的金属元素。试回答:

(1)B元素在周期表中的位置为___________________________________;

(2)将D的单质投入A2C中,反应后得到一种无色溶液。E的单质在该无色溶液中反应的离子方程式为__________________________________________。

(3)经测定,A2C2为二元弱酸,其酸性比碳酸的还要弱,请写出其第一步电离的电离方程式___________________________________。过去常用硫酸处理BaO2来制备制备A2C2,写出该反应的离子方程式___________________________;

现在实验室可以将过氧化钠加入到水中来制取A2C2,写出该反应的化学方程式_______________________________________________________________;

(4)废印刷电路板上含有铜,以往的回收方法是将其灼烧使铜转化为氧化铜,再用硫酸溶解。现改用A2C2和稀硫酸浸泡废印刷电路板既达到了上述目的,又保护了环境,试写出反应的离子方程式______________________________________。

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① DA能与水反应放氢气,反应化学方程式是                         

②若将1mol DA和1 mol E单质混合加入足量的水,生成气体的体积是(标准状况下)        L

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