— What does the fresh juice contain ?

—         of the juice         orange . It’s very pure .

A．Four – fifth , are

B．Four – fifths , are

C．Four – fifths , is

D．Four – fifth , is

混凝土轨枕的失效标准有（）。

A、承载槽面混凝土压溃，不能保持两股钢轨的均衡支承

B、钉孔损坏，挡肩破损无法修理

C、表面有裂纹

D、开裂或折断，不能保持轨距及两端钢轨的均衡承载力