关于记忆细胞的叙述错误的是()
A.已接受抗原刺激
B.仅限于B细胞
C.可自下而上数月至数年
D.参加淋巴细胞再循环
E.再次遇到抗原时能迅速增殖、分化
参考答案:B
—We're organizing a party next Saturday,and I'd like you to come.
—________!I have another one that day.Thank you just the same.
A.Good luck
B.What a pity
C.Never do it again
D.Well done
构造层次依次为:结构层、找平层、防水层、保温层、隔离层、保护层,属()屋面。