抗体的化学本质是[ ]
A.脂质
B.核酸
C.多糖
D.球蛋白
答案:D
If you any problems when you arrive at the airport, give me a ring.
A.come up with
B.set about
C.run into
D.put aside
个体趋向或接受某种刺激而获得满足称为()
A、诱因
B、需要
C、正诱因
D、负诱因