治疗阵发性室上性心动过速的最佳钙拮抗药是（）
A.硝苯地平
B.维拉帕米
C.尼莫地平
D.氟桂嗪
E.尼群地平
参考答案：B
I don't want to buy the dog _____ leg is broken. [ ]
A. that
B. whom
C. which
D. whose
简述矿物磁性的分类，及其分选特点。
