对填料的选择原则错误的是（）。A、单位体积填料的表面积要大，

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问题单项选择题

对填料的选择原则错误的是（）。

A、单位体积填料的表面积要大，气液相接触的自由体积要大

B、对气相阻力要小，即空隙截面积小

C、质量要轻，机械强度要高，耐介质腐蚀，经久耐用，价格低廉

D、根据操作压力和介质来选择填料的材质

答案

参考答案：B

完形填空

补全对话从方框中所给的选项中选择正确的句子补全以下对话。(10分)

Students: Good morning, Miss Lin.

Miss Lin: 　小题1:　　 Today, we'll talk about a new bird flu. It has hit some Chinese cities.

Monitor: 　小题2:　

Miss Lin: Yes, it is. It's reported that about 35 people have been ill.

Monitor: 　小题3:　

Miss Lin: We should keep away from animals. And we ought to wash our hands correctly.

Monitor: 　小题4:　

Miss Lin: It should take at least 20 seconds each time. 　　小题5:　 See a doctor at once if you have a high fever or have trouble breathing.

单项选择题

形位公差中的圆度公差带是（）。

A.圆

B.圆柱体

C.两同心圆之间的区域

D.圆柱面