—Are you pleased with what he has done?

—It couldn’t be____. Why didn’t he put more effort into his work?

A．any worse

B．much better

C．so bad

D．the best

（10肇庆市2）．见下图，下面对混凝土中“钢”的描述错误的是（   ）

A．金属材料

B．是一种合金

C．是纯净物

D．在潮湿条件下容易生锈