高钙血症常见的原因除外()
A.维生素D缺乏
B.钙溢出进入细胞外液
C.原发性甲状旁腺功能亢进
D.肾小管对钙重吸收增加
E.肠道对钙的吸收增加
参考答案:A
--- Who ______ it be that is singing in the next room?
--- It _______ be Lucy, but I am not sure.
A.can ; may
B.may ; can
C.can; must
D.must; may
计算题:用圆钢加工一正六边形条料,正六方形对边尺寸为24毫米,求最小应选用多粗的圆钢?