题图所示砖砌体和钢筋混凝土构造柱组成的组合墙。已知墙厚240mm，构造柱截面尺寸240mm÷240mm，/₁=/₂=1700mm，计算高度3.8m。配置4φ12HPB235钢筋，砖墙采用MU10砖，M5混合砂浆砌筑，构造柱采用C20的混凝土。

该组合墙的强度系数与下列（）项数值最为接近。

A．0.611

B．0.703

C．0.456

D．0.513

E-mail , as well as cellphones, _____an important part in daily communication.

A．have played

B．play

C．are playing

D．is playing