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问题 选择题

下列关于二氧化碳用途的描述中，不正确的是

A．冶炼金属

B．人工降雨

C．用作气体灭火剂

D．用于生产碳酸饮料

答案

答案：A

题目分析：固态二氧化碳可以用于人工降雨；二氧化碳不能燃烧也不支持燃烧，可做灭火剂；二氧化碳溶于水形成碳酸，可用于生产碳酸饮料。

二氧化碳不能冶炼金属。选A。

点评：性质决定用途，二氧化碳用途广泛，皆跟其性质有关。

探究题

在“探究摩擦力大小与哪些因素有关”的实验中，同学们提出以下几种猜想：

A．与压力大小有关；

B．与接触面的粗糙程度有关；

C．与接触面积大小有关。

（1）如图所示是小芳同学的实验操作，其错误之处是____________________。

（2）小芳在老师指导下纠正了操作，拉动弹簧测力计，使木块沿水平方向做_________直线运动，并记录实验数据。

 在木块上分别放不同的砝码，重复（2）的操作，记录的实验数据如下表所示。

（3）本实验用了控制变量法，控制的变量是接触面的粗糙程度和_________，变量是________。小芳同学的实验可以验证了猜想__________（选填上述猜想的字母序号）。

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单项选择题

Not everyone in the world requires the same amount of living space. The amount of space a person needs around him is a cultural difference, not an economic one. Knowing your own psychological space needs is important because they ply affect your choices, including, for example, the number of bedrooms in the home. If you were brought up in a two child family and both you and your sister or brother had your own bedrooms, the chances are if you have two children or more, that you also will offer separate bedrooms for them. In America, for example, they train people to want to have their own rooms by giving them their own rooms when they are babies. This is very unusual in the world. In many other countries, the baby sleeps in the same bed with his parents or in bed near them.
The space in the home also shows a lot about psychological space needs. Some families gather closer to each other and the size of their house has nothing to do with it. Others have separate little corners where family members go to be alone.
Although it is true that psychological space needs are not decided by economic reasons, they sometimes have to be changed a little because of economic pressure. It is almost impossible, however, to completely change your psychological space needs.

Which of the following is true according to the passage

A．Americans are trained to live in large rooms at birth.
B．Economic situation decides one’s amount of space needs.
C．People in various countries demand different psychological space.
D．Knowing your psychological space needs is important, as it affects your future.
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