— I hear that Tony was seriously injured in an accident the other day. 

— Yes, _____ news came as _____ shock (震惊) to all of us. [ ]

A. the; the

B. a; 不填

C. the; a

D. 不填; a

保存菌种的最好方法是()

A．置牛奶中

B．制成明胶片

C．置卵黄培养基中

D．置半固体培养基中

E．冷冻真空干燥法