抗体可分为（）
A.抗毒素
B.抗菌性抗体
C.中和抗体
D.调理素
E.补体
参考答案：A, B, C, D
在△ABC中，若∠A+∠B=90°，AC=5，BC=3，则AB=（ ），AB边上的高CE=（ ）。
When he heard the ____ news that an earthquake occurred in Sichuan, a ____ look came into his face.[ ]
A. frightened; frightened
B. frightened; frightening
C. frightening; frightening
D. frightening; frightened
