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问题 选择题

已知化学方程式X＋2O2CO2＋2H2O，下列对X的判断不正确的是[ ]

A．X是一种最简单的有机化合物

B．一定含碳、氢、氧三种元素

C．X是一种重要的气体燃料

D．X的化学式是CH4

答案

答案：B

填空题
从下面方框中选择适当的选项填入短文中，使短文通顺、完整。选项中有两项是多余的。
A. but      B. gives      C. nobody       D. history       E. patient       F. everyone    G. tired     H. looks      I. cheers        J. teacher       K. always       L. millions of
In my life, I have a lot of friends,  小题1: there is a special one who I'm the most thankful to. I first knew him when I began to go to school. He has been with me ever since.
Though he   小题2: serious, he is really fun as you get close to him. He is very quiet, smart and knowledgeable.  He knows every language of the world, all the events of   小题3:, all the
thoughts of great scientists and so on. He is admired(钦佩) by   小题4: who meets him.
To me, he has been a great 小题5: as well. He first taught me the secrets of my own language and then those of others. With these keys, he showed us how to unlock all the arts and sciences of man.
My friend is quite  小题6: . Although I am slow in understanding. I can return to him again and again, and he is   小题7: ready to teach me. When I am  小题8: , he makes me relaxed. When I am lonely, he stays with me silently. When I am sad,  he   小题9:  me up. He is a friend not only to me, but also to  小题10: people around the world. Shall I tell you his name? His name is “Reading”.
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单项选择题

污水中只含有两类污染物，但需预测其浓度的水质参数数目≥10，这类污水水质的复杂程度属( )。

A．复杂

B．中等

C．简单

D．一般
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