1 you.. dont have to... drive there . you can take the train .

2 you ... dont have to. play tennis to enjoy watching tennis matches

3 you .. dont have to . buy me present though I always appreciate it when you do .

4 It is really important to remember . You .mustn't. forget .

5 you ..mustn't.. tell anybody . It is a big secret .

6 we are already late . We ..mustn't.. waste any more time .

7 this is a sterile area . It must be kept clean . you ..mustn't.. bring any food or drink in here .

8 you ..dont have to.. come at 8.00 . come at whatever time suits you .

9 you ..mustn't.. smoke in this area . It is forbidden .

10 i ..dont have to. go back again . the treatment in finished.

11 Jesns are not allowed in this company . you .mustn't.. wear jeans.

12 you .dont have to. be mad to work here but it helps .

13 you ...dont have to.. buy the text book for this course , you can borrow mine.

14 you ...mustn't.. smoke is a gas station .

15 this bus is free! you ..dont have to.. buy a ticket .

16 you ....mustn't.. enter the park if your dog is not on a leash.

$1.$ don't have to 

$2.$ don't have to

$3.$ don't have to

$4.$ mustn't 

$5.$ mustn't 

$6.$ mustn't 

$7.$ mustn't 

$8.$ don't have to

$9.$ mustn't 

$10.$ don't have to

$11.$ mustn't 

$12.$ don't have to

$13.$ don't have to

$14.$ mustn't 

$15.$ don't have to

$16.$ mustn't 

$=========="$

- S + mustn't + V (Bare): Chỉ hành động mang tính bắt buộc.

- S + don't have to + V (Bare): Chỉ hành động không mang tính bắt buộc, có thể làm hoặc không.