SDH网络中的某个网元上报B1性能值，与该点通过光纤直接相连的下游网元一定会报告B1性能值。（）
参考答案：错
The pilot asked all the passengers on board to remain _____ as the plane was landing. [ ]
A. seat
B. seating
C. seated
D. to be seating
比一比，组成词语。 钓( ) 妨( ) 询( ) 钩( ) 防( ) 讯( )
