— Bill is ill. Do you know what's wrong with lum?            

—Poor boy. His illness is the_________of eating unhealthy food.     [ ]

A. result

B. cause

C. reason

D. end

嗜肺军团菌的特性，正确的是（）

A.常用革兰染色，阴性

B.最适生长温度为30℃

C.营养要求高，在含血清的培养基上生长

D.兼性厌氧菌，胞外寄生

E.可引起医院感染