There _____ a pen and two rubbers in the pencil box. [ ]
A. am
B. is
C. are
D. be
答案:B
球墨铸铁的机械性能接近甚至超过某些()
A.钢
B.低碳钢
C.中碳钢
D.高碳钢
患者,女,45岁。诊见气壅息粗,四肢僵直,牙关紧闭,脉象沉实,治宜选用
A.苏合香丸
B.玉枢丹
C.搐鼻散
D.五磨饮子
E.通瘀煎