`@` 5 câu chủ động với mustn't chuyển sang bị động :

`1.`

`-` You mustn't smoke in this area.

`=>` Smoking in this area mustn't be allowed.

`2.` 

`-` Guests mustn't disturb the wildlife.

`=>` Disturbing the wildlife mustn't be done by guests.

`3.` 

`-` People mustn't litter in the park.

`=>` Littering in the park mustn't be allowed by people.

`4.` 

`-` You mustn't waste water. 

`=>` Water mustn't be wasted by you

`5.` 

`-` You mustn't break the rules.

`=>` The rules mustn't be broken by you

$-----------------$

`@` Kiến thức :

`-` Mustn't `+` V `→` Mustn't `+` be `+` V3/V-ed. : Không phải làm gì...