7 Complete the sentences about the UK with must, mustn't, should or shouldn't IN THE UK .. 3 you must be over 17 to drive a car. you ?... buy a licence for your television. you say 'please' and 'thank you' as much as you can. you *... walk or sit on the grass in some parks. you ... give your seat to old people on a crowded bus or train. you take a present if someone invites you to their house. you ?... open an umbrella inside the house. you .... call your teacher by his or her first name,