提高人群被动特异性免疫力通过接种（）
A.丙种球蛋白
B.灭活疫苗
C.菌苗
D.抗毒素
E.类毒素
参考答案：A, D
下列植物中，体内含有输导组织的是：
A．水绵
B．衣藻
C．墙藓
D．肾蕨
He insisted ________ me with the handbag, though I told him I could manage it myself. [ ]
A. help
B. in helping
C. on helping
D. to help
