题目

The pot-bellied pig is too big to sleep in the house, _________I have to make it a big one. A. or                           B. so                           C. but 答案：BB细胞接受抗原刺激后，经过增殖分化形成（　　） A、浆细胞和记忆细胞B、T细胞和效应T细胞C、效应T细胞和效应B细胞D、巨噬细胞和效应B细胞