坏死性龈口炎的致病菌为

A．梭形杆菌和疏螺旋体

B．放线菌

C．链球菌和螺旋体

D．梭形杆菌和密螺旋体

E．丝状菌

He _____ in his English Test Paper. His teacher was very angry with him.       [ ]

A. makes some mistakes    

B. make a mistake

C. made few mistakes        

D. made many mistakes