When the seat belt sign goes on everyone should go unfasten their seat belt
举一反三
- Fasten the seat belt while the Fasten Seat Belt Sign is on.（ ）
- Fasten the seat belt while the Fasten Seat Belt Sign is on.
- Fasten the seat belt while the Fasten Seat Belt Sign is on.
- Fasten the seat belt while the Fasten Seat Belt Sign is on.
- When to fasten the seat belt? A: for take-off B: for landing C: during air turbulence D: whenever the Fasten Seat Belt sign is on