公安机关专政职能的专政手段是打击、制裁、改造、监督。( )
参考答案：对
As soon as the shoes that the boy wanted to buy were_____ in the store, the salesgirl called him. [ ]
A. present
B. possible
C. available
D. convenient
哪项符合维生素D缺乏性佝偻病激期改变（）
A.血清钙正常
B.血清磷正常
C.钙磷乘积大多高于30
D.碱性磷酸酶增高
E.长骨X线检查骨质密度增高
