1. 把下列词组的序号填入相应的位置。

A. on a bus   B. on a train    C. on a bike D. on a car    E. on a plane    F. on a boat

1. （1） You mustn't walk around during landing.
3. （2） You mustn't talk to the driver .
5. （3） You must wear a helmet .
7. （4） You must wear a seatbelt
9. （5） You mustn't put your head out of the window .
11. （6） You must wear a lifejacket .