渐缩喷管出口气体的流速是()。
A、M<1
B、M>1
C、M=1
参考答案:A, C
to advertisements constantly can help to change people’s opinions over time
A.Exposed
B.Being exposed
C.Exposing
D.To be exposed
结核结节与假结核结节的区别是前者有干酪样坏死物。