Where ___ dirt, there are flies. [ ]
A. there has
B. is
C. there is
D. there are
答案:C
治疗原发性三叉神经痛,近来认为也能奏效的药物是()
A.苯妥英钠
B.维生素B12
C.卡马西平(酰胺咪嗪)
D.苯巴比妥
E.地西泮
最常用的混凝剂有()以及()。