妊娠期营养不良将导致母体营养不良性水肿、骨质软化症和（）
A.营养性缺碘
B.营养性缺锌
C.营养性缺硒
D.营养性贫血
E.营养性缺铁
参考答案：D
In the short run, the average product of labor:（）
A. is initially declining but must increase at some point.
B. is upward sloping if the firm is experiencing diminishing marginal returns to labor.
C. is at A maximum where it intersects the marginal product of labor curve.
以下各功能中，( )不需要硬件的支持。
A．中断系统B．地址映射C．进程调度D．时钟管理E．页面调入F．文件打开
