6. You must see the headmaster.
⇒You've to see the headmaster.
7.Why isn't this TV working ?
⇒What is the matter with this TV?
8. When is Jonh and Marry's wedding?
⇒When are John and Marry going to get married?
9. Most people can understand him when he speaks English
⇒He can make most people understand when he speaks English
10. We can't afford to buy this car
⇒The car is too expensive for us to buy.