How ____ he is! He is always acting _____. He is really a _____.

A．foolish, foolishly, fool

B．fool, foolish, fool

C．foolish, fool, fool

D．fool, foolishly, fool

关于免疫，错误的是 （）

A.抵御病原体入侵

B.可防止肿瘤发生

C.清除自身衰老死亡细胞

D.对机体总是有利的

E.维持内环境稳定