维生素D缺乏可引起手足抽搐的原因是()
A．钙吸收减少
B．甲状旁腺反应迟钝
C．食物中含钙量低
D．血钙磷乘积<30
E．尿钙排出过多
参考答案：B
A desk is made _____ wood, and paper is made _____ wood, too. [ ]
A. from, from
B. of, of
C. of, from
D. from, of
德育网络的沟通方式中，家校互访是最常见的个别访问，它具有针对性强、具体、细致、深入等特点。
