①胰岛A细胞、肝细胞、胰高血糖素、肝糖原;
②浆细胞、肺结核杆菌、抗体、抗原;
③甲状腺细胞、垂体细胞、甲状腺激素、受体;
④传出神经元、传入神经元、神经递质、受体.
A:①③
B:①④
C:②④
D:②③
“乙肝”疫苗由乙肝病毒灭活制成.注射“乙肝”疫苗的目的是( )
We will have to choose a person to __________ our class to take part in the competition.