婴儿佝偻病的主要病因是（）。
A.缺乏钙离子
B.缺乏维生素D
C.缺乏维生素A
D.钙磷比例不当
E.甲状旁腺素不足
参考答案：B
With the aid of the most advanced equipment, new facts about the ancient pyramids in Egypt
have recently .[ ]
A. brought to light
B. seen the light
C. thrown light upon
D. come to light
对人民警察采取禁闭措施的期限为1天至（）。
A.5天
B.7天
C.10天
D.15天
