I asked two students the way to the post office, but of them knew.
---How often are the Olympic Games held? ---_____four years.
The ice isn’t ______________ to skate on.
---Are you going to ____________ your friends to your party? ---Yes, sure.
---Must I clean the floor now? ---__________. It is too dirty.
---How long may I _____________ the book? ---Two weeks.