By the end of last year, another new gymnasium        in Beijing.

A．would be completed

B．was being completed

C．has been completed

D．had been completed

下列比较关系式正确的是

A．真密度＞粒子密度＞松密度

B．粒子密度＞真密度＞松密度

C．松密度＞真密度＞粒子密度

D．粒子密度＞松密度＞真密度

E．真密度＞松密度＞粒子密度