慢性肾衰竭引起贫血的主要原因（）。
A.利钠激素增多
B.甲状旁腺激素增多
C.运铁蛋白
D.血磷升高
E.促红细胞生成因子减少
参考答案：E
_______ that he isn't adequate to the present job, he devotes all his spare time to studying professional
skills. [ ]
A. To concern
B. Concerning
C. Having concerned
D. Concerned
我国的凭证式国债，在持有人需要提前兑取时，除偿还本金外，利息按实际持有天数及相应的利率档次计算，经办机构按兑付本金的2‰收取手续费。（）
