* * 正常菌群不包括（）

A.革兰阳性需氧菌及兼性厌氧菌

B.革兰阴性需氧菌及兼性厌氧菌

C.白色葡萄球菌

D.专性厌氧菌

E.支原体及假丝酵母菌

She couldn't remember names of her college classmates，but his name frequently ________ to her

memory.[ ]

A．happened  

B．occurred

C．struck  

D．compared