答案：D
慢性肾衰竭患者合并显微囊性骨炎的直接因素是（）
A.营养不良
B.继发性甲状旁腺功能亢进
C.铝中毒
D.肾分泌磷功能下降
E.1，25-二羟维生素D3合成减少
Keep on trying and you'll find the method to the problem ____. [ ]
A. on time
B. in time
C. at times
D. some time
