A21. How long did it 1) take you to get to the airport?
A22. My grandfather 2) has to visit the doctor once a month.
A23. We 3) don't have to go to work on Saturday.
A24. Where are your parents, Henry? They 1) are working in the garden.
A25. The Greens will play badminton in the park if it 2) isn't windy.
A26. Have you ever 1) been to London? 3) aren't 2) seen .
A27. Moscow is 3) bigger than Paris.
A28. This film is 2) worse than the one I saw last week.
A29. This book is 3) the most interesting I have ever read.
A30. Simon runs 2) quickly.