— I was riding along the street and all of a sudden, a car cut in and knocked me down.

— You can never be________careful in the street.[ ]

A. much  

B. very  

C. so  

D. too

单核细胞增生李斯特菌在半固体培养基中培养可出现（）。

A.沉淀生长

B.浑浊生长

C.表面形成菌膜

D.不生长

E.倒伞形生长