常见的肺炎主要由下列哪种病原体引起______
A．肺炎支原体 B．病毒C．肺炎链球菌 D．军团菌
参考答案：C
We were cut off from the outside world by the sudden flood; what’s worse, our food ______.
A．was run out
B．was running out
C．has run out of
D．has been run out
下列那一个指令可以删除空目录？（）
A.rmdir
B.more
C.cp
D.cls
