将测量值3.1248修约为三位有效数字，正确的修约结果是 A．3.1 B．3.12

May I have two ___________, please?[ ]

A. bottle of pop 

B. bottles of pop 

C. pops

D. bottles of pops

仔细观察画中的同学受到了什么伤害？请你为他保护自我提供两个有效办法。

___________________________________________________________________________________________

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At present, we are studying a total of nine subjects, ________ I think is physics.

A．of them the most difficult

B．and the most difficult of which

C．the most difficult of them

D．the most difficult of which

某高度为50m的高层剪力墙结构，抗震等级为二级，其中一底部墙肢的截面尺寸如右图所示：混凝土强度等级为C30，剪力墙采用对称配筋，纵向钢筋为HRB335钢，竖向和水平分布钢筋为HPB235钢。a_s=a_s’=25mm。

考虑地震作用组合时，墙肢的剪力设计值V_w=2600kN，轴向压力设计值N=3375kN，计算截面处剪跨比λ=1.5。假定剪力墙水平钢筋间距s=200mm，试问剪力墙水平钢筋的面积A_sh（单位：mm²）与（）项数值最为接近。

A．341

B．290

C．142

D．196