引起社区获得性肺炎占首位的革兰阴性杆菌是（）
A.肺炎克雷伯杆菌
B.大肠埃希菌
C.军团菌
D.支原体
E.铜绿假单胞菌
参考答案：A
15．－Tom, you've got an A in the final English exam. Congratulations!
－Thanks. But I never thought the result would come out so fast. The papers_____when I left the teacher's office just now.
A．were marking
B．were marked
C．were being marked
D．had been marked
选粉机或其他设备报警停车，是什么原因造成的？
