问题
选择题
一氧化碳和二氧化碳性质不同的根本原因是它们的（ ）
A．相对分子质量不同
B．分子构成不同
C．用途不同
D．组成元素不同
答案
一氧化碳和二氧化碳的组成元素相同，但是分子构成不同，所以化学性质不同．
故选B．
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一氧化碳和二氧化碳性质不同的根本原因是它们的（ ）
A．相对分子质量不同
B．分子构成不同
C．用途不同
D．组成元素不同
一氧化碳和二氧化碳的组成元素相同，但是分子构成不同，所以化学性质不同．
故选B．
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| Christmas will come soon. The radio stations (广播电台) are playing Christmas music, and the stores 1 very busy. People are doing their Christmas shopping. Many families have got Christmas trees 2 their homes already. At this time of the year people make or 3 presents for their families. Lisa is going to buy a new book for her elder sister. Her elder sister likes 4 . Her families usually get together 5 Christmas Day. Her elder sister lives in another city far away, 6 she always come by plane. 7 is going to arrive on Christmas Eve. Then Lisa is going to put a 8 in the living room, and put the presents under the tree. They don't open them until Christmas 9 . They are very 10 to receive (收到) presents. | ||||
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