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问题 选择题

“黑火药”是我国古代四大发明之一，它由硝酸钾、硫磺、木炭组成，属于（　　）

A．纯净物

B．化合物

C．氧化物

D．混合物

答案

“黑火药”由硝酸钾、硫磺、木炭等物质组成，属于混合物．

故选D．

选择题
选择正确的字母组成单词。
( ) 1. ga__e
( ) 2. s__ng
( ) 3. r__d
( ) 4. g__een		A. o
B. m                                                                                          
C. r
D. e
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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.

According to the writer of the passage, psychological space needs ______.

A．are not affected by income at all
B．can hardly be changed altogether
C．can be changed if you make up your mind to do so
D．have nothing to do with cultural background
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