Don't let yourself be            by a small failure in the experiment Try again.[ ]

A. turned down        

B. cast down        

C. put down        

D. made down

判断灭菌是否彻底的指标是（）。

A.芽胞

B.荚膜

C.鞭毛

D.普通菌毛

E.性菌毛