下列各项中属于主动免疫制剂的是()
A.菌苗
B.疫苗
C.抗毒素
D.类毒素
E.丙种球蛋白
参考答案：A, B, D
— Why does the boy keep crying?
— It is ______ he has lost his favorite car model.
A．since
B．so
C．when
D．because
紫舌的主病是（）
A.气滞
B.血瘀
C.痰凝
D.津亏
E.中毒
