When hitting a solid object such as ship or an airplane,the radar waves are reflected back（）they came.

A.in the way

B.the way

C.by the way

D.through the path

呼吸衰竭最常见的诱因( )

A．呼吸系统的急性感染
B．手术创伤
C．肺水肿
D．镇静剂
E．慢性阻塞性肺气肿