对肠道杆菌的共同特性叙述错误的是（）。

A.均为革兰阴性杆菌

B.均为条件致病菌

C.鉴别依据生化反应

D.鉴别依据抗原构造

E.均含有菌体（O）抗原

He feels lonely in the school because he has _____ friends.[ ]

A. a few

B. few

C. a little

D. little