What will be most frequently mentioned during safety check announcement?
A.seat belt
B.seat back
C.tray table
D.window shade
正确答案：seat belt；seat back；tray table；window shade
What will be most frequently mentioned during safety check announcement?
A.seat belt
B.seat back
C.tray table
D.window shade
正确答案：seat belt；seat back；tray table；window shade